 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued February 10, 2015          Decided September 4, 2015

                       No. 13-3097

               UNITED STATES OF AMERICA,
                       APPELLEE

                             v.

               MICHAEL ANTHONY WEAVER,
                      APPELLANT


        Appeal from the United States District Court
                for the District of Columbia
                   (No. 1:10-cr-00096-1)


    Beverly G. Dyer, Assistant Federal Public Defender,
argued the cause for appellant. With her on the briefs was
A.J. Kramer, Federal Public Defender. Tony Axam, Jr.,
Assistant Federal Public Defender, entered an appearance.

     Patricia A. Heffernan, Assistant U.S. Attorney, argued
the cause for appellee. With her on the brief were Ronald C.
Machen, Jr., U.S. Attorney, and Elizabeth Trosman,
Elizabeth H. Danello, and John P. Dominguez, Assistant U.S.
Attorneys.

    Before: HENDERSON, ROGERS and PILLARD, Circuit
Judges.
                              2
    Opinion for the Court filed by Circuit Judge PILLARD.

    Dissenting opinion filed by Circuit Judge HENDERSON.

     PILLARD, Circuit Judge: This appeal requires us to
answer a question left unresolved by the Supreme Court in
Hudson v. Michigan, 547 U.S. 586 (2006): Whether the
exclusionary rule is applicable when law enforcement officers
violate the Fourth Amendment’s knock-and-announce rule
while executing a warrant to arrest a suspect found at home.

      The knock-and-announce rule requires that, before
officers executing a warrant enter a home, they knock on the
door and announce their identity and purpose, and then wait a
reasonable time before forcibly entering. In Hudson, the
Supreme Court held that, when officers violate that rule in
executing a search warrant, exclusion of the evidence they
find is not an appropriate remedy. The Court reasoned that
the officers would have discovered the evidence in any event
when they went through the house under the authority of the
valid search warrant. As the Court emphasized, the knock-
and-announce rule “has never protected” any “interest in
preventing the government from seeing or taking evidence
described in a warrant.” Id. at 594. Where officers armed
with a search warrant have a judicially-sanctioned prerogative
to invade the privacy of the home, the knock-and-announce
violation does not cause the seizure of the disputed evidence.
In that context, the exclusionary remedy’s significant costs
outweigh its minimal privacy-shielding role, and its deterrent
utility is “not worth a lot.” Id. at 596.

    Unlike the officers in Hudson, who had a warrant to
search the home, the officers here acted pursuant to a warrant
to arrest a person. An arrest warrant reflects no judicial
determination of grounds to search the home; rather, it
                               3
evidences probable cause to believe that the arrestee has
committed a crime, and authorizes his arrest wherever he
might be found. If an arrestee is found away from home—at
work, on the street, or at someone else’s home—the privacy
of his home remains inviolate. So, too, if an arrestee is not at
home when officers seek him there, or if he comes to the door
and makes himself available for arrest, the arrest warrant does
not authorize officers to enter the home. Any prerogative an
arrest warrant may confer to enter a home is thus narrow and
highly contingent on the particular circumstances of the
arrest.

     An individual subject to an arrest warrant accordingly
retains a robust privacy interest in the home’s interior. That
privacy interest is protected by requiring law enforcement
officers executing an arrest warrant to knock, announce their
identity and purpose, and provide the arrestee with the
opportunity to come to the door before they barge in. And,
where evidence is obtained because officers violated the
knock-and-announce rule in executing an arrest warrant at the
arrestee’s home, the exclusionary rule retains its remedial
force.    Under Hudson’s own analytic approach, then,
exclusion of the evidence may be an appropriate remedy.

     Justice Kennedy took care to underscore in his separate
opinion in Hudson that “the continued operation of the
exclusionary rule, as settled and defined by our precedents, is
not in doubt.” Id. at 603. He provided the fifth vote for the
majority opinion because the knock-and-announce violation
before the court was “not sufficiently related to the later
discovery of evidence to justify suppression.” Id. The critical
inquiry was there, as it is here, whether the knock-and-
announce violation could “properly be described as having
caused the discovery of evidence,” id. at 604, and, if so,
whether its costs outweigh its benefits. Where the
                               4
“requirement of causation” that animates the exclusionary
rule has not been obviated as it was by the search warrant in
Hudson, id., and where the exclusionary rule retains remedial
force to protect the core Fourth Amendment privacy interest
in the home, cf. id. at 603-04, we consider it our duty to apply
it.

     We thus analyze the factors the Court considered in
Hudson to determine whether the exclusionary rule applies
when the knock-and-announce rule is violated in the arrest
warrant context. We consider whether the violation causes
the seizure of evidence such that evidentiary suppression
furthers the interests underlying the knock-and-announce rule,
and whether the benefits of applying the exclusionary rule
outweigh its costs. Examining those factors, we conclude that
exclusion was the appropriate remedy here, where officers
executing a warrant for defendant Michael Weaver’s arrest
sought him at home, violated the knock-and-announce rule,
and discovered Weaver’s marijuana upon their forced entry
into Weaver’s apartment. Accordingly, we reverse the district
court’s decision to the contrary.

                               I.

     Federal agents from the Bureau of Alcohol, Tobacco,
Firearms, and Explosives began investigating defendant
Michael Weaver in 2008, when he came to their attention
during the course of a drug-related investigation targeting a
different suspect. As part of their investigation into Weaver,
the agents searched through trash outside his home and found
marijuana. They also learned from the target of the first
investigation that Weaver had sold drugs for more than a year
and trafficked in significant quantities of marijuana. The
agents executed a warrant to search Weaver’s residence in
late 2009 and discovered more than 500 grams of marijuana,
                              5
$38,000 in cash, and drug packaging materials. The agents
also reviewed Weaver’s bank records and identified regular,
unexplained cash deposits and a balance of more than
$100,000 from unknown sources. In April 2010, the agents
relied on that information to obtain a warrant for Weaver’s
arrest. Prosecutors indicted Weaver on 52 separate counts,
including possession with intent to distribute marijuana and
money laundering.

     The government was unable to apprehend Weaver until
2012, when the agents learned the location of his new
residence. After arriving at Weaver’s building, the agents
knocked on his apartment door twice. There was no answer,
but the agents heard movement inside. They were not
concerned that Weaver would flee out a window because the
apartment was on a high floor. Less than a minute later, the
agents announced “police” and immediately used a key they
had obtained from the building’s concierge to unlock the
door. They did not inform Weaver that they had a warrant to
arrest him. As the agents attempted to open the door,
someone inside tried to hold the door closed. The officers
were able to push the door open, and, after a brief struggle,
they subdued Weaver, arrested him, and removed him from
the apartment.

     In the course of arresting Weaver, the officers smelled
marijuana. One of the officers testified that as soon as he
“came in” and “looked to the left” or “turned left” toward the
kitchen, he observed “bags of marijuana” on the counter.
Based on those observations, the officers obtained a search
warrant for the apartment and found several kilograms of
marijuana, two tablets of oxycodone, a bag of the drug
methylenexdioxymethcathinone (commonly referred to as
MDMC, or bath salts), and nearly $10,000 in cash. The
government then charged Weaver with three additional
                               6
counts: one count of possession with intent to distribute
marijuana and two counts of possession of a controlled
substance.

    At trial, Weaver moved to suppress the evidence seized
during the 2012 search of his apartment. He contended that
the warrant authorizing that search derived solely from the
observations agents made while executing the arrest warrants,
and that the agents were not legally authorized to be in his
apartment when they made those observations because they
had violated the knock-and-announce rule. Weaver further
argued that Hudson did not preclude the application of the
exclusionary rule to his case.

     The district court rejected Weaver’s contentions and
denied his motion to suppress. The district court first
concluded that there was no knock-and-announce violation
because the officers knocked, announced “police,” and then
waited a reasonable time before opening the door. Even if
there had been a violation, the court held that Weaver would
not prevail because it concluded that Hudson held the
exclusionary rule inapplicable to knock-and-announce
violations generally.

     In a separate order, the district court held that Weaver’s
speedy trial rights were violated with respect to the first 52
counts of the indictment, and so dismissed them. The
government then entered into an agreement with Weaver
concerning the more recent counts of the indictment. The
government dismissed the counts for possession of oxycodone
and MDMC, and Weaver agreed to a bench trial on stipulated
facts on the remaining charge of possession with intent to
distribute marijuana. After that trial, the district court found
Weaver guilty.
                              7
     Weaver appeals the district court’s denial of his
suppression motion. On such an appeal, we review the
court’s legal conclusions de novo and its findings of fact for
clear error. United States v. Pindell, 336 F.3d 1049, 1052
(D.C. Cir. 2003).

                              II.

                              A.

     The Fourth Amendment protects “[t]he right of the
people to be secure in their persons, houses, papers, and
effects, against unreasonable searches and seizures.” U.S.
Const. Amend. IV. The constitutional reasonableness of a
search or seizure in the home depends on, among other things,
whether law enforcement officers have complied with the
knock-and-announce rule. Wilson v. Arkansas, 514 U.S. 927,
931, 934 (1995); see also 18 U.S.C. § 3109 (setting forth a
statutory knock-and-announcement requirement). The rule
requires, subject to exceptions not relevant here, that law
enforcement officers executing a warrant—whether for search
or arrest—knock on an individual’s door, announce their
identity and purpose, and then wait a reasonable amount of
time before forcibly entering a home. Wilson, 514 U.S. at
934-36; see also United States v. Banks, 540 U.S. 31, 38-39
(2003); Sabbath v. United States, 391 U.S. 585, 588 & n.2
(1968); Miller v. United States, 357 U.S. 301, 312-14 (1958).

    Notwithstanding the district court’s conclusion to the
contrary, there is no dispute on this record that the
constitutional safeguards imposed by the knock-and-announce
rule were violated here. As the government correctly
concedes on appeal, federal agents violated the rule by failing
to announce their purpose before entering Weaver’s
apartment. Appellee Br. 19-20; see also Miller, 357 U.S. at
309-10; United States v. Wylie, 462 F.2d 1178, 1184-85 (D.C.
                               8
Cir. 1972). Both parties also agree that unless the agents were
legally present in Weaver’s home when they viewed the
marijuana, their observations could not serve as a lawful basis
for the issuance of the search warrant. Appellee Br. 41 n.11;
Appellant Br. 22-23; see Horton v. California, 496 U.S. 128,
136 (1990). If the officers’ forcible entry into Weaver’s home
was unlawful, their presence in his home was also unlawful,
and their observations could not serve as the basis for a search
warrant. Consequently, the sole question before us is whether
the exclusionary rule applies to evidence obtained as a result
of a knock-and-announce violation committed when law
enforcement officers execute an arrest warrant, as opposed to
a search warrant.

     Where it applies, the exclusionary rule prohibits the
government from introducing in its case in chief evidence
obtained in violation of the Fourth Amendment. See, e.g.,
Mapp v. Ohio, 367 U.S. 643, 655 (1961); Weeks v. United
States, 232 U.S. 383, 398 (1914). Evidentiary exclusion
“compel[s] respect for the constitutional guaranty in the only
effectively available way—by removing the incentive to
disregard” the Fourth Amendment’s commands. Elkins v.
United States, 364 U.S. 206, 217 (1960). The Supreme Court
has acknowledged, however, that exclusion is not appropriate
in every case. Application of the rule is warranted only when
its objectives are “most efficaciously served.” United States
v. Leon, 468 U.S. 897, 908 (1984) (internal quotation marks
omitted); see also Davis v. United States, 131 S. Ct. 2419,
2426-27 (2011); Herring v. United States, 555 U.S. 135, 140-
41 (2009). “Where suppression fails to yield ‘appreciable
deterrence,’ exclusion is ‘clearly unwarranted.’” Davis, 131
S. Ct. at 2426-27.
                              9
                              B.

     In Hudson, the Supreme Court considered whether
exclusion was warranted when law enforcement officers
violated the knock-and-announce rule while executing a
search warrant. 547 U.S. at 588. Two factors governed its
consideration: whether there was a causal link between the
violation and the seizure of evidence and whether the rule’s
deterrence benefits outweighed the costs of excluding
probative evidence.

     As to causation, the Hudson Court reasoned that the
exclusionary rule is only triggered when the constitutional
violation is “a ‘but-for’ cause of obtaining evidence,”
provided that causal connection is not “too attenuated.” Id. at
592. In Hudson, “the constitutional violation of an illegal
manner of entry was not a but-for cause of obtaining the
evidence.” Id. That is because the knock-and-announce
violation did not expand the breadth of the search authority
conferred on the officers by the search warrant they had in
hand, pursuant to which they already were privileged to
obtain the incriminating evidence. Id.

     Even if the knock-and-announce violation had been a
but-for cause of obtaining the evidence, causation in Hudson
was too attenuated. Id. at 592-93. Attenuation occurs “when
the causal connection is remote.” Id. at 593. Attenuation also
occurs, the Court explained, when “the interest protected by
the constitutional guarantee that has been violated would not
be served by suppression of the evidence obtained.” Id.
Having held there was no but-for causation, the Court did not
analyze whether causation was too remote. It did hold,
however, that even if there were but-for causation, the
interests protected by the knock-and-announce rule
nonetheless would not, in the search warrant context, be
                               10
served by suppression of the evidence obtained. Id. at 593-
94. In that context, the Hudson Court observed, the knock-
and-announce rule protects personal safety, property, and a
residuum of privacy not obviated by the search warrant. It
protects personal safety by preventing violence by a surprised
resident. Id. at 594. It avoids destruction of the doorway of a
house when officers forcibly open it instead of using the
requisite knock and announcement of identity and purpose to
summon the homeowner to the door. Id. And it “protects
those elements of privacy and dignity that can be destroyed by
a sudden entrance” by giving residents an opportunity “to pull
on clothes[,] get out of bed,” and otherwise “collect
[themselves] before answering the door.” Id. (internal
quotation marks omitted). The Court emphasized that “the
knock-and-announce rule has never protected . . . one’s
interest in preventing the government from seeing or taking
evidence described in a warrant.” Id. As Justice Kennedy
vividly pointed out, “[w]hen . . . a violation results from want
of a 20–second pause but an ensuing, lawful search lasting
five hours discloses evidence of criminality, the failure to wait
at the door cannot properly be described as having caused the
discovery of evidence.”        Id. at 603-04 (Kennedy, J.,
concurring). “[T]he interests that were violated . . . ha[d]
nothing to do with the seizure of the evidence,” leading the
Court in Hudson to hold the exclusionary rule inapplicable.
Id. at 594 (majority opinion).

     The Court in Hudson separately examined whether the
“deterrence benefits” of applying the exclusionary rule to
violations of the knock-and-announce rule during search
warrant executions “outweigh its substantial social costs.” Id.
(internal quotation marks omitted). The most significant of
the “considerable” costs of applying the exclusionary rule is
the “grave adverse consequence that exclusion of relevant
incriminating evidence always entails,” namely “the risk of
                              11
releasing dangerous criminals into society.” Id. at 595. The
Court cautioned that allowing an exclusionary remedy also
could lead to a “flood” of defendants claiming knock-and-
announce violations, which would require judicial resolution
of complicated, fact-intensive issues. Id. It could also lead
officers to wait longer than constitutionally required before
entering a dwelling, and thus “produc[e] preventable violence
against officers in some cases, and the destruction of evidence
in many others.” Id.

     The Court weighed those costs against the deterrence
value of applying the exclusionary rule in the search warrant
context, which it concluded is minimal. Id. at 596. Violating
the warrant requirement altogether often produces
incriminating evidence not otherwise obtainable, see id., and
the exclusionary rule is needed to blunt that incentive, see
Mapp, 367 U.S. at 656; Elkins, 364 U.S. at 217. Violating the
knock-and-announce requirement when executing a search
warrant, by contrast, does not provide officers with an
opportunity to obtain evidence that the warrant, already in
hand, would not otherwise authorize them to get. Hudson,
547 U.S. at 596; see also id. at 592. (Where an unannounced
entry is needed to serve important law enforcement interests,
such as where officers have a reasonable suspicion that
evidentiary destruction or life-threatening resistance would
accompany a duly announced entry, the knock-and-announce
requirement is suspended. Id. at 596.) The Court concluded
that law enforcement officers armed with search warrants
have scant incentive to violate the knock-and-announce rule;
moreover, it noted, other deterrents—civil suits and the
increasing professionalism of police forces—are sufficient to
deter such violations. See id. at 596-99.

    As a result of those considerations, the Court held that
evidentiary exclusion was not required when officers violated
                               12
the knock-and-announce rule in the course of executing a
search warrant.

                              III.

                               A.

     Hudson has not answered the question before us. The
government argues, and the dissent agrees, that because the
exclusionary rule was held inapplicable in Hudson, it is
equally inapplicable here. We of course employ Hudson’s
legal framework in considering whether the exclusionary
remedy is appropriate here. But we cannot accept the
government’s contention that our analysis begins and ends
with the outcome of Hudson. We must independently
examine whether the logic of Hudson applies here to the same
effect, or whether the arrest warrant context at issue here is so
materially distinct that it requires a different result.

     The government and dissent propose we follow an
interpretation of Hudson that is divorced from its context.
They contend that Hudson held that the exclusionary rule has
no application to any violation of the knock-and-announce
rule, regardless of whether the violation occurred during the
execution of a warrant to search the home or to arrest a
suspect. Dissent at 1. In their view, Hudson already held that
the exclusionary rule is inapplicable whenever the knock-and-
announce rule is violated—even where officers have only an
arrest warrant and not a search warrant.

     Hudson does not support that approach. The dissent
plucks general statements from Hudson to argue that the
Court intended its holding to extend beyond the search
warrant context. See Dissent at 1 & n.1; see also id. at 9-11.
But the Court, contrary to the dissent’s characterization,
articulated the question before it in search-warrant-specific
                                13
terms: The opening sentence of the opinion stated that the
question presented was “whether violation of the ‘knock-and-
announce’ rule requires the suppression of all evidence found
in the search.” 547 U.S. at 588 (emphasis added). The
Court’s reasoning was grounded in the context before it.
When describing the interests the knock-and-announce rule
protected, for example, it emphasized that “[w]hat the knock-
and-announce rule has never protected . . . is one’s interest in
preventing the government from seeing or taking evidence
described in a warrant.” Id. at 594 (emphasis added). Search
warrants—and not arrest warrants—“describe” “evidence”
and authorize officers to “take” that evidence. The precedents
discussed and relied on by both the majority opinion and
Justice Kennedy’s concurrence are the Court’s precedents
concerning search warrants, see id. at 593 (discussing cases
“excluding the fruits of unlawful warrantless searches”),
further suggesting that the Court did not conceive of its
decision as sweepingly as the government contends.1

     We reject the government’s and the dissent’s insistence
that the issue here has already been decided by Hudson. It
should go without saying that a holding can be understood
only by reference to the context of the case in which it was
rendered. See Phelps v. United States, 421 U.S. 330, 333-34
(1975) (cautioning that the Court’s statements must be “read
in the context of the facts of th[e] case” before it); Armour &

1
  The precedents the Court cited and discussed involved home
warrants and searches, not arrest warrants executed at home. 547
U.S. at 590-91, 593, 602 (citing United States v. Ramirez, 523 U.S.
65 (1998); Mapp v. Ohio, 367 U.S. 643 (1961); Weeks v. United
States, 232 U.S. 383 (1914)); see also 547 U.S. at 603 (Kennedy, J.,
concurring in part and concurring in the judgment) (citing
Ramirez).
                              14
Co. v. Wantock, 323 U.S. 126, 132-33 (1944) (emphasizing
that the Court’s “opinions are to be read in the light of the
facts of the case under discussion,” as the Court cannot
practically “writ[e] into them every limitation or variation
which might be suggested by the circumstances of cases not
before the Court.”).

     The Supreme Court’s Fourth Amendment cases vividly
illustrate that the precise scope and limits of a constitutional
principle articulated in one case often are not apparent until
the Court has had opportunities to apply it in new situations
that help to elucidate it. Compare Florida v. Jardines, 133 S.
Ct. 1409, 1415-16 (2013) (holding that the use of a drug-
sniffing dog on a homeowner’s porch was a search under the
Fourth Amendment), with United States v. Place, 462 U.S.
696, 707 (1983) (holding that a sniff by a narcotics-detection
dog of an individual’s luggage did not constitute a search
under the Fourth Amendment); see also Dissent at 6-7
(collecting cases charting the Court’s incremental approach to
creating exceptions to the exclusionary rule).

     The Court in United States v. Knotts, 460 U.S. 276, 278-
79, 281-82 (1983), for example, held that no search occurred
and thus no warrant was required when officers tracked
defendants’ whereabouts by placing a radio transmitter in a
drum of illicit drug ingredients, so that when defendants
picked up the drum they unwittingly carried the transmitter
with them. Defendants had no reasonable expectation of
privacy and thus no Fourth Amendment rights against the
government using that means to obtain information they
already were exposing to the public. Id. at 281-82. The next
year, in United States v. Karo, 468 U.S. 705 (1984), however,
the Court applied Knotts’s reasoning to support the opposite
result on analogous but materially different facts: A similar
use of a radio transmitter placed in a can of drug ingredients
                               15
violated the defendant’s Fourth Amendment rights because
the transmitter was used to track the defendant as he carried
the chemicals inside a private home. Id. at 707. United
States v. Jones, 132 S. Ct. 945 (2012), revealed yet another
important consideration. In Jones, the Court considered
whether the government’s installation of a GPS device on a
defendant’s car to monitor its movements on public roads
constituted a search. Id. at 948. The Court in Jones
distinguished Knotts and Karo, pointing out that in neither of
the prior cases had the Court been faced with a situation in
which the defendant possessed the property when the
government committed the trespass to insert the information-
gathering device. Id. at 952.

     We cannot presume that Hudson mandates the same
result for violations of the knock-and-announce rule in both
the search and arrest warrant contexts. Instead, we must
assess whether, as Weaver argues, the arrest warrant context
is materially distinguishable from the search warrant context.
The government’s and the dissent’s efforts to find in Hudson
a categorical rule deciding this case cannot be squared with
the pervasive and necessary incrementalism of judicial
decision making. Hudson addressed the propriety of the
exclusionary remedy for a knock-and-announce violation in
the search warrant context. The Court never mentioned the
parallel question as it arises in the context of executing arrest
warrants. For the reasons discussed in the next sections, we
conclude that the differences between search and arrest
warrants distinguish this case from Hudson.

                               B.

    The requirements for search warrants and arrest warrants
protect distinct privacy interests, and the two types of
warrants authorize law enforcement officers to take different
                              16
actions. The interests the knock-and-announce rule protects
correspondingly differ, depending on the type of warrant law
enforcement officers are executing.       Because of those
differences, the Court’s analysis in Hudson cannot apply the
same way or yield the same result here.

     An individual’s interest in protecting the privacy of his
home is of the highest order. See, e.g., Jardines, 133 S. Ct. at
1414; Kyllo v. United States, 533 U.S. 27, 31 (2001). As
Justice Kennedy underscored in Hudson,

    privacy and security in the home are central to the
    Fourth Amendment’s guarantees as explained in our
    decisions and as understood since the beginnings of
    the Republic. This common understanding ensures
    respect for the law and allegiance to our institutions,
    and it is an instrument for transmitting our
    Constitution to later generations undiminished in
    meaning and force. It bears repeating that it is a
    serious matter if law enforcement officers violate the
    sanctity of the home by ignoring the requisites of
    lawful entry.

547 U.S. at 603. “At the very core of the Fourth Amendment
stands the right of a man to retreat into his own home and
there be free from unreasonable governmental intrusion.”
Kyllo, 533 U.S. at 31 (internal quotation marks omitted); see
also Jardines, 133 S. Ct. at 1414 (“[W]hen it comes to the
Fourth Amendment, the home is first among equals.”);
Minnesota v. Carter, 525 U.S. 83, 99 (1998) (Kennedy, J.,
concurring) (“[I]t is beyond dispute that the home is entitled
to special protection as the center of the private lives of our
people.”); Payton, 445 U.S. at 585 (“[T]he physical entry of
the home is the chief evil against which the wording of the
                             17
Fourth Amendment is directed.” (internal quotation marks
omitted)).

     Law enforcement officers’ authority under an arrest
warrant to enter and search a home is both more conditional
and more circumscribed than their authority under a search
warrant. Officers armed with a search warrant may enter a
home and search for the items described in the warrant
anywhere in the home where those items might be located.
See Maryland v. Garrison, 480 U.S. 79, 84-85 (1987). An
arrest warrant, by contrast, authorizes a much more limited
intrusion into the home. See, e.g., Steagald v. United States,
451 U.S. 204, 213-14 & n.7 (1981); Payton v. New York, 445
U.S. 573, 603 (1980). In executing an arrest warrant, officers
may enter an individual’s home only when they have reason
to believe the arrestee is there, Payton, 445 U.S. at 603, may
look only where a person might reasonably be found, and
must stop searching once they locate him, Maryland v. Buie,
494 U.S. 325, 330, 332-33 (1990); United States v. Thomas,
429 F.3d 282, 287 (D.C. Cir. 2005).

     When officers have lawfully accessed an area of the
home in search of an arrestee, they may seize items in plain
view that they have probable cause to believe are evidence of
a crime. See, e.g., Arizona v. Hicks, 480 U.S. 321, 326
(1987); Coolidge v. New Hampshire, 403 U.S. 443, 465
(1971). Arresting officers must not routinely search every
room in a home; when arresting an individual at home, the
arrest warrant’s authority is confined to locating the person,
securing the area within his reach, and making a quick and
limited sweep of the immediately adjoining areas from which
an attack could be launched. See, e.g., Buie, 494 U.S. at 327,
334; Chimel v. California, 395 U.S. 752, 763, 766 (1969).
Officers may also perform a sweep of other areas of the home
if they have “articulable facts which . . . would warrant a
                                 18
reasonably prudent officer in believing that the area to be
swept harbors an individual posing a danger to those on the
arrest scene.” Buie, 494 U.S. at 334.2 Once officers find the
arrestee, however, they are no longer authorized by the arrest
warrant to enter other rooms in the home; the arrestee retains
an expectation of privacy in those areas. Id. at 333. In sum,
the timing and scope of lawful searches of a home pursuant to
an arrest warrant are limited by whether and where the
arrestee is in the home when he submits to arrest.

     An arrestee’s location at the time of arrest is likely to
depend on whether officers comply with the knock-and-
announce rule.      The knock-and-announce rule requires
officers to announce their presence and purpose and give an
arrestee an opportunity to open the door of his home. See
Miller, 357 U.S. at 308 (citing Semayne’s Case (1604) 77
Eng. Rep. 194, 195; 5 Co. Rep. 91a); Banks, 540 U.S. 31, 38-
39. Any governmental agent must “signify the cause of his
coming, and … make request to open doors.” Miller, 357 U.S.
at 308 (quoting Semayne’s Case 77 Eng. Rep. at 195).
Officers armed with an arrest warrant may only “break open
doors to take the person suspected, if upon demand he will not

2
  The dissent argues that we have mischaracterized Buie. Dissent at
22. That is not so. In Buie, the Supreme Court specifically
described the kind of sweep officers can make without reasonable
suspicion as “quick and limited.” 494 U.S. at 327. Such a sweep
“may extend only to a cursory inspection of those spaces where a
person may be found,” and may last “no longer than is necessary to
dispel the reasonable suspicion of danger and in any event no
longer than it takes to complete the arrest and depart the premises.”
Id. at 335-36. We agree that a sweep supported by a reasonable
suspicion may be more extensive. But, such a sweep must be
“justified by the circumstances,” id. at 335, and the government has
not argued such circumstances are present here.
                              19
surrender himself.” Accarino v. United States, 179 F.2d 456,
461 (D.C. Cir. 1949) (emphasis added) (internal quotation
marks omitted).

     As the Supreme Court recognizes, when officers break
the door of a home to arrest someone, they “invade[] the
precious interest of privacy summed up in the ancient adage
that a man’s house is his castle.” Miller, 357 U.S. at 307. In
the arrest warrant context, the knock-and-announce rule
protects the arrestee’s privacy as well as his property and the
officers’ safety. That privacy interest is not limited—as it is
in the face of a warrant to search the home—to providing the
arrestee with an opportunity to compose himself or get
dressed, but also enables the arrestee to preserve the privacy
of his “castle” by surrendering himself at the door. If an
arrestee so surrenders himself, officers cannot make the more
extensive intrusion into the home that they are authorized to
make when an arrestee does not come to the door. The
knock-and-announce rule consequently protects an arrestee’s
interest in shielding intimate details of his home from the
view of government agents.

     A person’s right to the privacy of his home does not
require him to have any special reason for claiming that
privacy; the Constitution recognizes a person’s privacy in the
home as valuable in and of itself. It is, however, easy to
understand the additional value of the knock-and-announce
rule to a person facing arrest at home, who may have any
number of reasons for wanting to surrender himself at the
door and shield the remainder of his home from view.
Someone living with his family might, for example, prefer to
surrender himself on his doorstep to avoid being arrested in
front of his family members, especially children. A person
may also desire to keep private and personal papers and
effects in the home, or the fact or identity of a guest, from
                             20
government agents’ view.          The Fourth Amendment’s
protection of the privacy of personal spaces, documents, and
things at home applies whether or not they are evidence of
wrongdoing or a potential source of embarrassment. “Every
householder, the good and the bad, the guilty and the
innocent, is entitled to the protection designed to secure the
common interest against unlawful invasion of the house.”
Miller, 357 U.S. at 313; see also Hicks, 480 U.S. at 329;
Carter, 525 U.S. at 110 (Ginsburg, J., dissenting).

                             C.

     Contrary to the argument advanced by the dissent, our
decision in United States v. Southerland, 466 F.3d 1083 (D.C.
Cir. 2006), does not “directly refute the search/arrest
distinction” just described. Dissent at 13. Southerland
involved a knock-and-announce violation during execution of
a search warrant. It was pending on appeal in this court when
the Supreme Court decided Hudson.             On reargument,
Southerland abandoned his constitutional claim and argued
that Hudson did not apply to the violation of his statutory
knock-and-announce right. 466 F.3d at 1083. We concluded
that the constitutional and statutory knock-and-announce rules
were one and the same, id. at 1085-86, making the
exclusionary remedy equally inapplicable to the violations
during Southerland’s and Hudson’s home searches, see id. at
1084-85.

     The dissent draws an unwarranted implication from
Southerland’s discussion of two older cases—Miller and
Sabbath—that had reversed denials of evidentiary
suppression. See Sabbath, 391 U.S. at 585-87; Miller, 357
U.S. at 303-04. Each of those cases involved violations of
statutory knock-and-announce provisions in an arrest context.
Southerland invoked those cases in his effort to distinguish
                             21
Hudson and salvage his exclusionary remedy on the ground
that Miller and Sabbath addressed statutory claims and held
suppression to be appropriate. 466 F.3d at 1084-85. We
rejected the proposed distinction between the constitutional
and statutory versions of the knock-and-announce rule. Id. at
1086. The fact that both Miller and Sabbath were arrest cases
was not relevant to Southerland, which was a search case; we
simply had no occasion to address whether the exclusionary
rule continues to apply to a knock-and-announce violation
committed when officers seek to arrest a suspect at home.

     The Supreme Court’s discussion in Hudson itself was
similarly limited. That Court referred to Miller and Sabbath
in confirming the common historical roots of the statutory and
constitutional knock-and-announce rules, but did not say
anything about overruling the suppression remedy where
officers fail to knock and announce before entering homes to
effectuate arrests. 547 U.S. at 589. Indeed, Miller and
Sabbath’s validation of the exclusionary remedy for knock
and announce violations in the arrest context—undisturbed by
Hudson—is more of an obstacle to the dissent’s position than
Southerland is to ours. Even the government here, which was
clearly aware of the Southerland case, see Appellee Br. at 19,
does not accord it the force that the dissent urges.

    In sum, we agree with Southerland that Hudson provides
the relevant legal framework for determining whether
exclusion is the appropriate remedy when officers violate the
knock-and-announce rule. But, for the reasons already
discussed, neither Hudson nor Southerland considered or
answered the question before us.
                                  22
                                  D.

    Finally, the out-of-circuit cases the dissent cites, Dissent
at 1 n.3, 11-12, provide at most weak support for the
proposition that Hudson applies in the arrest-warrant context.

     The First Circuit has held, as the dissent points out, that
“Hudson applies with equal force in the context of an arrest
warrant.” United States v. Pelletier, 469 F.3d 194, 199, 201
(1st Cir. 2006); see also United States v. Jones, 523 F.3d 31,
36-37 (1st Cir. 2008). The First Circuit’s decisions, however,
do not address the distinctions between arrest and search
warrants.3 Because we believe those distinctions are material
to Hudson’s analysis, the First Circuit’s failure to
acknowledge them undercuts those decisions’ persuasive
force.

     The other cases the dissent identifies are not even
arguably in conflict with our decision. See Dissent at 12
(citing United States v. Smith, 526 F.3d 306, 311 (6th Cir.
2008), and United States v. Ankeny, 502 F.3d 829, 835-36
(9th Cir. 2007)). Those cases concern application of Hudson
to the search warrant context, not the arrest warrant context.
The dissent quotes language from those opinions out of
context to support points not made by the opinions
themselves.4 In Smith, for example, the defendant argued that

3
  Moreover, it does not appear that in either Pelletier or Jones the
defendants brought those distinctions to the attention of the court,
nor, indeed, did the government in its briefing in Jones rely on
either Hudson or Pelletier.
4
  Several of the other cases and articles the dissent cites, see Dissent
at 1 nn. 2-3, 5, merely describe the holding of Hudson. Those cases
do not specify, let alone hold, that Hudson prevents application of
the exclusionary rule to a knock-and-announce violation in the
                                23
officers failed to abide by the knock-and-announce rule when
conducting a search, not when making an arrest. 526 F.3d at
308. The officers lacked a search warrant, but the court
concluded that their search of the defendant’s home was
nevertheless reasonable because he was under house arrest
and thus had a diminished expectation of privacy. Id. at 308-
09. The court concluded that Hudson “was not confined to
situations in which the officers violate the knock-and-
announce rule after obtaining a [search] warrant as opposed to
situations, like this one, where they allegedly violate the rule
when they need not obtain a warrant” in order to perform a
constitutionally valid home search. Id. at 311. Smith had no
occasion to consider whether Hudson was confined to search
as opposed to arrest cases.

     Similarly, Ankeny’s holding in no way conflicts with
ours. In that case, the defendant moved to suppress evidence
seized by officers because, he argued, the officers failed to
knock and announce their presence when executing a search
warrant. 502 F.3d at 833-34.5 The defendant contended that


arrest warrant context. We have not found imprecise descriptions
of Hudson in secondary sources or courts’ dicta to provide helpful
guidance in applying Hudson’s analysis to the current case.
Additionally, in two of the state-court cases the dissent invokes,
Dissent at 1 n.3, the courts held that evidentiary exclusion is the
appropriate remedy for violations of state knock-and-announce
rules. See State v. Cable, 51 So. 3d 434, 444 (Fla. 2010); Berumen
v. State, 182 P.3d 635, 642 (Alaska Ct. App. 2008).
5
  In Ankeny, the defendant had outstanding arrest warrants, but it
appears that officers entered his home pursuant to a search warrant.
502 F.3d at 833 (recounting that officer announced “police, search
warrant” before breaking down the defendant’s door). In any event,
if officers violated the knock-and-announce rule armed with both
arrest and search warrants, presumably the officers would, as in
                               24
his case was not governed by Hudson “because the police
could have obtained a no-knock warrant but failed to do so,”
but the court “decline[d] to limit Hudson so narrowly to its
facts.” Id. at 835-36. The court did not consider the propriety
of an exclusionary remedy for knock-and-announce violations
committed during the execution of arrest warrants. Despite
the dissent’s assertions to the contrary, neither Smith nor
Ankeny speak to whether or how Hudson applies when
officers violate the knock-and-announce rule when they lack a
search warrant and arrive at the house solely to execute a
warrant for the inhabitant’s arrest.

                               IV.

    Given the differences between search warrants and arrest
warrants, the conclusions drawn in Hudson do not resolve this
case. Instead, we must independently examine the factors
identified in Hudson—causation and the costs and benefits of
exclusion—to determine whether application of the
exclusionary rule is appropriate. Examining those factors, we
conclude that the exclusionary rule is the appropriate remedy
for a violation of the knock-and-announce rule committed
during execution of an arrest warrant.

                               A.

     We first consider causation. See Hudson, 547 U.S. at
592-93. In the arrest warrant context, the place where an
individual is arrested determines what officers might see and
where they are permitted to search. A knock-and-announce
violation, leading to an arrest inside the home rather than at
the front door, is thus the immediate cause of officers

Hudson, have a valid basis for seizure of the evidence independent
of the knock-and-announce violation, which is not the case here.
                              25
intruding further within a home than they otherwise would
and obtaining evidence that they are not authorized to see.
That clear and strong causal connection distinguishes this case
from Hudson.

     Law enforcement officers’ failure to knock and announce
deprives the arrestee of any opportunity to answer the door
and surrender himself at the threshold of his home. When not
properly summoned by officers knocking and announcing
their identity and purpose, an arrestee might be located
anywhere in the home, perhaps in a bedroom or on an upper
floor of a multi-level dwelling. As a result of entering
unannounced, the officers gain access to more—perhaps a
great deal more—of a home’s interior than they would have
had they fulfilled their constitutional obligation to knock,
announce, and allow the arrestee time to come to the door. As
officers move through a house to locate an arrestee, they are
able to view more portions of its interior. If they find the
arrestee in a study or bedroom, searching places within his
immediate reach and protectively sweeping adjacent areas is
likely to be more intrusive and revealing than it would have
been had those searches occurred on a front stoop or in a
foyer. Officers’ failure to knock and announce, therefore, can
cause them to view areas of the home and discover evidence
that they would not have otherwise have constitutional
authority to see. In such cases, the constitutional violation is
the direct cause of law enforcement officers obtaining
evidence beyond that which the warrant lawfully authorizes.

     Requiring officers to knock and announce when
executing an arrest warrant guards the privacy interest in the
home in a way that the same requirement cannot do when
officers have a warrant to search the home. Unlike officers
armed with a search warrant, officers armed solely with an
arrest warrant do not have the authority to examine any
                              26
papers, gather any effects, or search the various nooks and
crannies of an arrestee’s home. They are authorized to make
only the limited intrusion into the home necessary to locate
and seize the arrestee. See Payton, 445 U.S. at 603. Once
they locate the arrestee, officers may intrude no further. The
knock-and-announce rule, by providing an arrestee with the
opportunity to surrender himself at the door, thereby enables
the arrestee to minimize the scope of that intrusion and protect
the intimacies of his home from the officers’ view.
Suppressing evidence obtained in violation of the knock-and-
announce rule thus directly serves the interests protected by
the rule.

     The dissent presumes that, because the same substantive
knock-and-announce requirements apply in both the search
and arrest context, the rule protects the same interests. See
Dissent at 17-19. In Hudson, however, the Supreme Court
had no occasion to consider or specify the interests protected
by the requirement that officers knock and announce when
executing an arrest warrant. See 547 U.S. at 594 (“What the
knock-and-announce rule has never protected . . . is one’s
interest in preventing the government from seeing or taking
evidence described in a warrant.”). Hudson concluded that
the interest in privacy in the home that is obviated when a
judge issues a search warrant based on probable cause of
crime or evidence of crime in the home is an interest that the
knock-and-announce rule no longer serves. Our analysis
recognizes that the privacy interest in the home remains intact
when a judge has made only the different determination of
probable cause that a suspect has committed a crime
warranting arrest. Application of the knock-and-announce
rule in the arrest warrant context enables the arrestee to
protect his privacy at home by surrendering himself at the
door.
                                27
                                B.

     We next weigh, in the arrest warrant context, the costs of
excluding evidence obtained by violation of the knock-and-
announce rule against its benefits in protecting the Fourth
Amendment right to privacy in the home and deterring
violations of that right. See Hudson, 547 U.S. at 594-98.
Because application of the exclusionary rule here would result
in appreciable deterrence, the benefits of applying the rule
outweigh its acknowledged social costs.

    The costs of applying the exclusionary rule to this kind of
constitutional violation in the arrest warrant context are
similar to those described in Hudson: The courts will need to
expend resources to resolve close claims of knock-and-
announce rule violations, officers’ entry might be delayed by
knocking, announcing, and waiting for response, and, most
importantly, relevant, incriminating evidence will be rendered
unavailable at a defendant’s trial. Id. at 595.6

    Those costs are real, but they are outweighed by a
privacy interest and opportunity to deter its violation that is
substantially stronger here than the negligible privacy interest
and deterrence value in Hudson. As the Court observed in
Hudson, “the value of deterrence depends on the strength of
the incentive to commit the forbidden act.” Id. at 596.
Officers armed with only an arrest warrant—who, for
whatever reason, did not seek or were unable to obtain a
search warrant—have a strong incentive to violate the knock-

6
  The mere existence of that last cost, always present when the
exclusionary rule is applied, is insufficient in and of itself to
overcome an appropriate application of the rule. Cf. Leon, 468 U.S.
at 906-09. If it were otherwise, the exclusionary rule would not
exist.
                              28
and-announce rule. Entering a home unannounced to execute
an arrest warrant increases the chances that officers will gain
entry to parts of a home they would not otherwise have
entered to carry out the arrest, and will thereby give
themselves an opportunity to find incriminating evidence they
otherwise would never see.

     The facts of this case aptly highlight when and why
officers might want to violate the knock-and-announce rule.
The officers were executing an arrest warrant that was over
two years old, based on offenses committed even earlier. The
officers lacked recent incriminating evidence against Weaver.
By failing to knock and announce, they were able to obtain
new, valuable evidence from Weaver’s kitchen without a
search warrant and secure a superseding indictment that was
not susceptible to a speedy trial challenge. The government’s
ability to parlay an old arrest warrant into new evidence
supporting new charges demonstrates precisely why officers
armed with only an arrest warrant would be tempted to seek
the suspect at home and violate the knock-and-announce rule.

     Officers can conduct limited searches incident to a lawful
arrest in the home, as the dissent acknowledges. Dissent at
23. But the dissent fails to recognize that the scope and
intrusiveness of those searches varies depending on where in
the home the arrestee is located. By violating the knock-and-
announce rule, officers give themselves a better chance of
arresting an individual inside his home, where a search or
protective sweep will be more revealing than one conducted
on the home’s threshold.

     Given the strong incentives officers may have to violate
the rule, the deterrence calculus is starkly different here than
it was in Hudson. In Hudson, the Court’s balancing analysis
was driven, in large part, by its conclusion that the incentives
                               29
to violate the rule were weak and therefore that deterrence
was virtually worthless. 547 U.S. at 596. The opportunities
to gain evidence not otherwise accessible increase incentives
to violate the rule here, which correspondingly raises the
exclusionary rule’s deterrence value.       That appreciable
deterrence outweighs the costs of the rule.

     It would make little sense to jettison the exclusionary rule
simply because, as the dissent presumes, officers rarely
violate the knock-and-announce rule when executing an arrest
warrant.     If violations are rare, then the actual cost of
applying the exclusionary rule will be minimal. The courts
will not be flooded with cases claiming failures to observe the
rule and very few dangerous criminals will go free because of
officers’ missteps. Cf. Dissent at 20. The paucity of cases
challenging violations of the knock and announce rule when
officers execute an arrest warrant may very well be due to the
deterrent effect of past applications of the exclusionary rule.
See generally Sabbath, 391 U.S. 585; Miller, 357 U.S. 301.

     Here in the arrest-warrant context, unlike in Hudson,
there are grounds to conclude that application of the
exclusionary rule to knock-and-announce violations would
result in appreciable deterrence of constitutional violations.
When application of the exclusionary rule provides beneficial
deterrence, and that benefit outweighs the costs of the rule, it
applies.

                               C.

     The government contends that its agents should not have
to wait for an arrestee to take any particular series of steps
that might shield his home from the agents’ view. The
government is correct insofar as agents need not, for example,
make every effort to enable an arrestee to open the door in a
manner that does not expose the interior of his home to view,
                             30
exit the dwelling, and close the door. But they must give him
an opportunity to come to the door. See Banks, 540 U.S. at
38-39. Here, by knocking but failing to announce their
purpose, the agents gave Weaver no opportunity to protect the
privacy of his home.

     The government also argues that even if Weaver had
surrendered himself, in this particular case the agents would
nonetheless have been able to make the observations that
justified the search warrant. The record does not support that
conclusion. Because the federal agents violated the knock-
and-announce rule, Weaver was not given a chance to
surrender himself peacefully at the doorway of his unit or in
the hallway of his building. Instead, he struggled with
officers who pushed their way inside and eventually
overpowered him in order to effectuate the arrest. The record
does not reveal how much access to the apartment that
struggle gave the agents beyond what they otherwise would
have had. It is also unclear whether, given the layout of
Weaver’s apartment and the location of the drugs, the officers
would have been able to see and smell the marijuana plants
from the threshold of his unit if Weaver had opened the door
and surrendered himself there.

     The only evidence in the record is that agents were not
able to observe the drugs until they had entered Weaver’s
apartment: An agent executing the warrant testified that “[a]s
soon as [he] went in the door, [he] smelled the fresh
marijuana,” and that after he entered the apartment and looked
to his left he saw the marijuana. The record does not specify
how far into the apartment the agent went before he saw the
marijuana, how much farther into the apartment he was able
to enter as a result of the struggle to subdue Weaver, or
whether the marijuana was visible from the doorway. The
government has thus failed to create a record that would
                              31
enable us to conclude that the agents would have made the
same observations had they knocked, announced, and arrested
Weaver on his threshold. Nor has the government argued
that, even if Weaver had surrendered himself at the threshold
of his apartment, the drugs would have been observed during
a protective sweep of the areas adjacent to where Weaver was
arrested.

                            * * *

     For all of the foregoing reasons, we conclude that the
exclusionary rule is the appropriate remedy for knock-and-
announce violations in the execution of arrest warrants at a
person’s home. The parties agree that the officers did not
satisfy the rule’s dictates here. The district court should have
excluded the fruits of that constitutional violation.
Consequently, we reverse the district court’s denial of
Weaver’s suppression motion and remand for further
proceedings.

                                                    So ordered.
     KAREN LECRAFT HENDERSON, Circuit Judge, dissenting:
I am convinced the exclusionary rule does not apply to a
violation of the Fourth Amendment knock-and-announce
requirement, period. I had thought that was plain from the
U.S. Supreme Court’s decision in Hudson v. Michigan, 547
U.S. 586 (2006). My colleagues conclude, however, that
because Hudson involved a knock-and-announce violation
during the execution of a search warrant, it is limited to that
context and does not apply to a knock-and-announce violation
during the execution of an arrest warrant. Yet, nothing in
Hudson supports their view. Hudson held that all violations
of the knock-and-announce requirement are exempt from the
exclusionary rule and my colleagues’ attempt to limit its
reasoning to search warrants is unpersuasive. Indeed, the
majority, concurrence and dissent in Hudson would all be
surprised by my colleagues’ narrow reading. 1 As would
every member of this Court in 2006, 2 our sister circuits, 3

1
    See Hudson, 547 U.S. at 590 (defining question presented broadly as
“whether the exclusionary rule is appropriate for violation of the knock-
and-announce requirement”); id. at 588 (same); id. at 603–04 (Kennedy,
J., concurring in part and concurring in judgment); id. at 604 (Breyer, J.,
dissenting) (“[T]he Fourth Amendment normally requires law
enforcement officers to knock and announce their presence before entering
a dwelling. Today’s opinion holds that evidence seized from a home
following a violation of this requirement need not be suppressed.”).
2
  See United States v. Southerland, 466 F.3d 1083, 1083 (D.C. Cir. 2006)
(“Hudson’s holding [is] that the exclusionary rule did not apply to Fourth
Amendment knock-and-announce violations”), opinion unanimously
endorsed by Irons footnote, 466 F.3d at 1084 n.1.
3
   See, e.g., United States v. Pelletier, 469 F.3d 194, 201 (1st Cir. 2006)
(“Hudson applies with equal force in the context of an arrest warrant.”);
United States v. Smith, 526 F.3d 306, 311 (6th Cir. 2008) (“Nor, contrary
to [defendant’s] suggestion, does Hudson apply only when the officers
have a search warrant.”); United States v. Ankeny, 502 F.3d 829, 835–36
(9th Cir. 2007) (“[W]e decline to limit Hudson so narrowly to its facts.”);
United States v. Cos, 498 F.3d 1115, 1132 n.3 (10th Cir. 2007) (Hudson
“held that, when a particular kind of mistake is made by police officers
themselves—a violation of the Fourth Amendment’s knock-and-announce
                                      2
scholars on both sides of the exclusionary-rule debate 4 and
even Hudson’s lawyer. 5 The majority opinion in this case

requirement—the exclusionary rule is not applicable” (emphasis added));
United States v. Collins, 714 F.3d 540, 543 (7th Cir. 2013) (“Hudson . . .
holds that exclusion is not an appropriate remedy for violations of the
knock-and-announce rule.”); see also State v. Cable, 51 So. 3d 434, 441
(Fla. 2010) (stating, in arrest-warrant case, that “[u]nder Hudson, it is clear
that the exclusionary rule does not apply to Fourth Amendment knock-
and-announce violations”); Berumen v. State, 182 P.3d 635, 637 (Alaska
Ct. App. 2008) (same); State v. Marcum, No. 04-CO-66, ¶ 15, 2006 WL
3849861, at *3 (Ohio Ct. App. Dec. 28, 2006) (“Based on Hudson, no
evidence should have been suppressed due to a violation of the knock-and-
announce rule” during execution of arrest warrant); In re Frank S., 47
Cal. Rptr. 3d 320, 324 (Ct. App. 2006) (“Defendant’s contention that
Hudson applies only where the police have a search warrant is not
persuasive. Hudson held that a violation of the knock-and-announce rule
does not justify application of the exclusionary rule. The rule turns on the
nature of the constitutional violation at issue, not the nature of the police’s
authority for entering the home.” (citations omitted)).
4
   See, e.g., James J. Tomkovicz, Hudson v. Michigan and the Future of
Fourth Amendment Exclusion, 93 IOWA L. REV. 1819, 1839–41 & n.111
(2008) (explaining why Hudson cannot be limited to search warrants);
1 WAYNE R. LAFAVE, SEARCH & SEIZURE: A TREATISE ON THE FOURTH
AMENDMENT § 1.6(h) & n.165 (5th ed. 2014) (“Whatever one might think
of Hudson’s fruit-of-the-poisonous-tree holding, the majority’s . . .
alternate deterrence/costs holding . . . is open to broader application . . . .
Applying only a fruits analysis, it would seem that notwithstanding
Hudson there would be instances in which items not named in the warrant
would be deemed the fruit of a premature entry or an entry without notice
because absent that violation the evidence would not have been
discovered. But . . . it is to be doubted that it could likewise be said that
there is a greater need for deterrence of those knock-and-announce
violations that serendipitously produce such evidence.” (citation and some
footnotes omitted)); 2 DRUG ABUSE & THE LAW SOURCEBOOK § 9:14
(2014) (“The [Hudson] Court’s . . . balancing [of] the deterrence benefit
against the social cost of exclusion[] is likely to lead to the same result
regardless of whether the entry is to serve a search warrant or an arrest
warrant.”); Mark A. Summers, The Constable Blunders but Isn’t
Punished: Does Hudson v. Michigan’s Abolition of the Exclusionary Rule
Extend Beyond Knock-and-Announce Violations?, 10 BARRY L. REV. 25,
                                     3
will not only create a direct circuit split, see United States v.
Jones, 523 F.3d 31, 36 (1st Cir. 2008), but it will “produc[e]
preventable violence against officers,” “releas[e] dangerous
criminals into society” and generate a “flood” of burdensome
litigation. Hudson, 547 U.S. at 595; see also infra pp.19–21.
Accordingly, I respectfully dissent.

                         I. BACKGROUND

     The knock-and-announce requirement arises whenever a
police officer seeks to enter someone’s residence without
permission. See Sabbath v. United States, 391 U.S. 585, 589–
90 (1968). Before making such entry, an officer must knock,
announce his authority and purpose (“Police! I have a
warrant!”) and wait a reasonable time for an answer. See
Miller v. United States, 357 U.S. 301, 308–09 (1958); United
States v. Banks, 540 U.S. 31, 41 (2003). The requirements,
not surprisingly, are subject to exceptions. See, e.g., Miller,
357 U.S. at 310 (police need not announce purpose if
defendant already knows they are there to arrest him).
Moreover, an officer can bypass the knock-and-announce
requirement entirely if he has a “reasonable suspicion of
exigency or futility.” Banks, 540 U.S. at 37 n.3. Exigent

37 (2008) (“Because the[] interests [identified in Hudson] are the same in
every knock-and-announce rule case, there are no knock-and-announce
violations where applying the exclusionary remedy would be justified.”);
John B. Rayburn, Note, What Is “Blowing in the Wind”? Reopening the
Exclusionary Rule Debate, 110 W. VA. L. REV. 793, 823–24 (2008)
(“extend[ing] Hudson to the execution of arrest warrants . . . seem[s] to be
elementary and non-problematic”).
5
    David A. Moran, The End of the Exclusionary Rule, Among Other
Things: The Roberts Court Takes on the Fourth Amendment, 2006 CATO
SUP. CT. REV. 283, 283 (“[In] my 5-4 loss in Hudson v. Michigan . . . , the
Court held that when the police violate the Fourth Amendment ‘knock and
announce requirement’ the normal Fourth Amendment remedy, exclusion
of the evidence found after the violation, does not apply.”).
                                    4
circumstances include anticipated physical violence,
apprehending an escaped prisoner and preventing the
destruction of evidence. See Brigham City, Utah v. Stuart,
547 U.S. 398, 406 (2006); Wilson v. Arkansas, 514 U.S. 927,
936 (1995); Richards v. Wisconsin, 520 U.S. 385, 394 (1997).

    The United States inherited the knock-and-announce rule
from the English common law. See Hudson, 547 U.S. at 589;
see also Miller, 357 U.S. at 313 (knock-and-announce
requirement is “a tradition embedded in Anglo-American
law”). It is usually traced to Semayne’s Case—a 17th century
decision from the King’s Bench—although its origins may be
more ancient still. See Wilson, 514 U.S. at 931–32 & n.2; see
also Semayne’s Case, (1604) 77 Eng. Rep. 194 (K.B.) 196; 5
Co. Rep. 91 a, 91 b (citing 1275 statute and noting it was then
“but an affirmance of the common law”). For federal law-
enforcement officers, the knock-and-announce requirement
has been mandated by statute since 1917. See Act of June 15,
1917, tit. XI, § 8, 40 Stat. 229. The current version provides:

     The officer may break open any outer or inner door
     or window of a house, or any part of a house, or
     anything therein, to execute a search warrant, if,
     after notice of his authority and purpose, he is
     refused admittance or when necessary to liberate
     himself or a person aiding him in the execution of
     the warrant.

18 U.S.C. § 3109 (emphasis added). 6 By its terms, section
3109 governs the execution of “search warrant[s]” only. See

6
    Section 3109 also applies, by reference, to local law-enforcement
officers operating in the District of Columbia. See D.C. CODE § 23-524(a)
(“An officer executing a warrant directing a search of a dwelling house or
other building or a vehicle shall execute such warrant in accordance with
section 3109 of Title 18, United States Code.”).
                             5
Southerland, 466 F.3d at 1085. And, under the common law,
the knock-and-announce requirement “had not been extended
conclusively” to the arrest context at the Founding or even
through the Civil War. See Wilson, 514 U.S. at 935.
Nevertheless, courts “gradually” extended the common-law
requirement to arrests as well. Id. This Court, for example,
did so in Accarino v. United States, 179 F.2d 456 (D.C. Cir.
1949).

    In 1995, the Supreme Court clarified in Wilson v.
Arkansas that the knock-and-announce requirement is not
only a creature of statute and common law, but also a
requirement of the U.S. Constitution. See 514 U.S. at 934.
Specifically, the Fourth Amendment protects “[t]he right of
the people to be secure in their . . . houses . . . against
unreasonable searches and seizures,” U.S. CONST., amend. IV,
and the knock-and-announce requirement “forms a part of the
Fourth Amendment reasonableness inquiry,” Wilson, 514 U.S.
at 930. The Wilson Court declined, however, to decide the
remedy for a knock-and-announce violation, leaving that
question for another day. See id. at 937 n.4.

     Nevertheless, this Court had already answered the
question. Long before Wilson, we determined that the knock-
and-announce requirement was grounded in the Fourth
Amendment. See, e.g., McKnight v. United States, 183 F.2d
977, 978 (D.C. Cir. 1950). And we applied the exclusionary
rule to evidence obtained in violation of both the
constitutional      and    statutory   knock-and-announce
requirements. See, e.g., Gatewood v. United States, 209 F.2d
789, 791–92 (D.C. Cir. 1953); Woods v. United States, 240
F.2d 37, 39–40 (D.C. Cir. 1956). Yet, our cases were largely
a product of the times. The Supreme Court’s decisions during
that era suggested that, once a violation of the Fourth
Amendment occurred, the fruits of that violation must
                               6
necessarily be suppressed. See, e.g., Mapp v. Ohio, 367 U.S.
643, 654 (1961) (“all evidence obtained by an
unconstitutional search and seizure [is] inadmissible in a
federal court” (emphasis added) (citing Elkins v. United
States, 364 U.S. 206, 213 (1960))); Whiteley v. Warden, Wyo.
State Penitentiary, 401 U.S. 560, 568–69 (1971) (because
“petitioner’s arrest violated his constitutional rights under the
Fourth and Fourteenth Amendments[,] the evidence secured
as an incident thereto should have been excluded”).

     Those days, however, are long gone. “Subsequent case
law” from the Supreme Court “rejected [a] reflexive
application of the exclusionary rule.” Arizona v. Evans, 514
U.S. 1, 13 (1995); see also Hudson, 547 U.S. at 591
(“Expansive dicta in Mapp . . . suggested wide scope for the
exclusionary rule. . . . But we have long since rejected that
approach.” (citations omitted)). Instead, suppression is a “last
resort, not [a] first impulse.” Hudson, 547 U.S. at 591. Given
its “costly toll upon truth-seeking and law enforcement
objectives,” the party “urging application” of the exclusionary
rule shoulders a “high” burden. Pa. Bd. of Probation and
Parole v. Scott, 524 U.S. 357, 364–65 (1998) (quotation
marks omitted); see also Davis v. United States, 131 S. Ct.
2419, 2427 (2011) (“[Exclusion’s] bottom-line effect, in
many cases, is to suppress the truth and set the criminal loose
in the community without punishment. Our cases hold that
society must swallow this bitter pill when necessary, but only
as a last resort.” (citation and quotation marks omitted)).

    The Supreme Court has recognized several exceptions to
the exclusionary rule. The rule does not apply if the
constitutional violation is not the but-for cause of the
discovery of the evidence, see Murray v. United States, 487
U.S. 533, 537 (1988); Nix v. Williams, 467 U.S. 431, 444
(1984), or if the causal link is too “attenuated,” Wong Sun v.
                              7
United States, 371 U.S. 471, 487 (1963). Additionally, over
the last forty years, the Supreme Court has repeatedly
exempted whole categories of cases from the exclusionary
rule’s reach. See, e.g., Davis, 131 S. Ct. at 2423–24 (search
compliant with subsequently overruled precedent); Illinois v.
Krull, 480 U.S. 340, 349 (1987) (search compliant with
statute later deemed unconstitutional); Herring v. United
States, 555 U.S. 135, 137 (2009) (violation caused by police
employee’s clerical error); Evans, 514 U.S. at 16 (violation
caused by court employee’s clerical error); Massachusetts v.
Sheppard, 468 U.S. 981, 990–91 (1984) (violation caused by
magistrate judge’s clerical error); United States v. Leon, 468
U.S. 897, 922 (1984) (evidence obtained in reasonable
reliance on defective search warrant); Scott, 524 U.S. at 359
(parole revocation hearings); INS v. Lopez-Mendoza, 468 U.S.
1032, 1050 (1984) (civil deportation hearings); Stone v.
Powell, 428 U.S. 465, 494–95 (1976) (federal habeas review);
United States v. Calandra, 414 U.S. 338, 354 (1974) (grand
jury proceedings); United States v. Havens, 446 U.S. 620, 627
(1980) (evidence used to impeach defendant); United States v.
Janis, 428 U.S. 433, 460 (1976) (evidence seized by state
police and used in federal civil proceedings). In doing so, the
Supreme Court applies a balancing test: the Court will not
extend the exclusionary rule to a particular context unless the
deterrence benefits outweigh the societal costs. See, e.g.,
Leon, 468 U.S. at 909–10.

    Hudson v. Michigan falls neatly within this line of cases.
In Hudson, the Supreme Court finally answered the question
it had left unanswered in Wilson: namely, “whether the
exclusionary rule is appropriate for violation of the knock-
and-announce requirement.” Hudson, 547 U.S. at 590. The
Court said “no” for two independent reasons. First, a knock-
and-announce violation is too “attenuated” from the seizure of
evidence to warrant exclusion. See id. at 591–94. Second,
                                      8
and “[q]uite apart from the requirement of unattenuated
causation,” id. at 594, under the exclusionary-rule balancing
test, the deterrence benefit of suppression does not outweigh
the social costs. See id. at 594–99.

     Shortly after Hudson was decided, we had the
opportunity to determine its reach. In United States v.
Southerland, we assessed whether “Hudson’s holding that the
exclusionary rule did not apply to Fourth Amendment knock-
and-announce violations” also applies to statutory knock-and-
announce violations under section 3109. 466 F.3d at 1083.
We concluded that it does. See id. at 1086. We noted that the
standards governing section 3109, the Fourth Amendment and
the common law have “merged” so that “[t]here is now one
uniform knock-and-announce rule.” Id. at 1085–86; see also
Ramirez, 523 U.S. at 73 (“§ 3109 codifies the common law in
this area, and the common law in turn informs the Fourth
Amendment”). Unsurprisingly then, “each of the reasons[7]
Hudson gave for not applying the exclusionary rule to knock-

7
  The Southerland Court identified the Hudson “reasons” as follows:
     that the knock-and-announce requirement does not protect an
     individual’s interest in shielding “potential evidence from the
     government’s eyes,” Hudson, 126 S. Ct. at 2165; that
     “imposing th[e] massive remedy” of suppression “for a knock-
     and-announce violation would generate a constant flood of
     alleged failures to observe the rule,” id. at 2165–66; that
     questions about whether the police waited long enough before
     entering would be “difficult for the trial court to determine and
     even more difficult for an appellate court to review,” id. at
     2166; that any deterrent value from suppressing evidence in
     these cases would not be “worth a lot,” id.; that civil damage
     actions would still provide some deterrence, id. at 2166–68; and
     that “[a]nother development over the past half-century that
     deters civil-rights violations is the increasing professionalism of
     police forces, including a new emphasis on internal police
     discipline,” id. at 2168.
466 F.3d at 1084 (alterations in original).
                              9
and-announce violations of the Fourth Amendment applies
equally to violations of § 3109.” Southerland, 466 F.3d at
1084. Southerland acknowledged that earlier Supreme Court
precedent appeared to apply the exclusionary rule to
violations of section 3109. See id. at 1084–85 (discussing
Miller, 357 U.S. 301, and Sabbath, 391 U.S. 585). But those
cases did not technically apply section 3109 because they
dealt with knock-and-announce violations in connection with
arrests, not search warrants. Id. at 1085. More importantly,
to the extent the arrest cases may have required exclusion, we
concluded they were overruled by Hudson. See id. at 1085–
86; see also id. at 1086 (“[W]e think it plain that Hudson, not
Miller and Sabbath, now must control. Not only is Hudson
the Court’s most recent pronouncement about whether
evidence should be excluded as a remedy for knock-and-
announce violations, but it is also the Supreme Court’s only
thorough analysis of the issue.”)             Accordingly, in
Southerland, we held that the exclusionary rule does not apply
to violations of section 3109 and expressly overruled contrary
circuit precedent. See id. at 1086, 1084 n.1.

                       II. ANALYSIS

     Weaver contends—and my colleagues agree—that
Hudson v. Michigan is limited to search warrants and,
because the knock-and-announce violation here occurred
during the execution of an arrest warrant, the exclusionary
rule is back in play. Yet I find the attempt to distinguish
Hudson completely unpersuasive. Hudson’s holding contains
no search-warrant limitation and its reasoning applies equally
to searches and arrests.

                  A. HUDSON’S HOLDING

    Hudson involved a knock-and-announce violation that
occurred during the execution of a search warrant. See 547
                                   10
U.S. at 588. That fact does not mean, however, that Hudson’s
holding is limited to the search-warrant context:

     Every case is “limited to its facts,” if by that phrase
     one means that the court based its judgment on the
     facts presented to it. But most cases are also decided
     with reference to some more general normative
     principle which extends beyond the specific
     circumstances of the case before the court. Indeed, it
     is the existence of such broader norms which
     distinguishes a decision which is principled and
     rational from one which is ad hoc and arbitrary.

Robinson v. Diamond Hous. Corp., 463 F.2d 853, 862 (D.C.
Cir. 1972). Here, for instance, the Hudson Court framed the
issue broadly. See 547 U.S. at 590 (“The issue here is . . .
whether the exclusionary rule is appropriate for violation of
the knock-and-announce requirement.”); id. at 588 (“We
decide whether violation of the ‘knock-and-announce’ rule
requires the suppression of all evidence found in the search.”).
These statements are not “pluck[ed]” out of context, Maj. Op.
12; they are the two instances in which the Hudson Court
framed the question presented. 8 And nowhere in the opinion
8
   My colleagues emphasize the word “search” in the Hudson Court’s
statement that “[w]e decide whether violation of the ‘knock-and-
announce’ rule requires the suppression of all evidence found in the
search.” Hudson, 547 U.S. at 588 (emphasis added). Their italicization is
unhelpful. The Court said “search,” not “search warrant.” Whenever the
police enter a residence to execute an arrest warrant and seize evidence
incident to arrest or in plain view, a “search” occurs.
     My colleagues also note that the Hudson Court “relied on . . .
precedents concerning search warrants.”           Maj. Op. 13.    That is
unsurprising, as the “[c]ases acknowledging a need to knock and announce
typically involve the execution of search warrants.” Tomkovicz, supra, at
1837 n.92 (collecting cases). In any event, the Hudson Court did not rely
exclusively on such precedents. Its attenuation analysis, for example, was
primarily grounded in New York v. Harris, 495 U.S. 14 (1990)—a case
                                   11
did the Hudson Court leave open the possibility of a different
outcome in the arrest context or draw any distinction between
searches and arrests.

     Such a distinction would make little sense conceptually.
There is but “one uniform knock-and-announce rule.”
Southerland, 466 F.3d at 1086. The rule governs all
unauthorized entries into a residence, whether the police have
a search warrant, an arrest warrant or no warrant at all. See
Miller, 357 U.S. at 306, 309. There is not one knock-and-
announce requirement for search warrants and another knock-
and-announce requirement for arrest warrants. Indeed, far
from sharply distinguishing between arrests and searches, the
case law expressly conflates them. See id. (knock-and-
announce violation of federal officer “to execute [an] arrest
without [a] warrant must be tested by criteria identical with
those” governing “entry to execute a search warrant” and
“arrest . . . by virtue of a warrant”); Sabbath, 391 U.S. at 588
(same). See also generally Michigan v. Summers, 452 U.S.
692, 704 (1981) (downplaying “the distinction between a
search warrant and an arrest warrant”); Malley v. Briggs, 475
U.S. 335, 344 n.6 (1986) (same). Indeed, the First Circuit has
expressly rejected the distinction my colleagues draw here.
See Pelletier, 469 F.3d at 201 (“Hudson applies with equal
force in the context of an arrest warrant.”); Jones, 523 F.3d at
36 (“In the wake of Hudson, we have recognized the absence
of an exclusionary rule for knock-and-announce violations,
provided the police have a valid arrest warrant . . . and reason
to believe the target is inside.”). 9 And other circuits have

involving a warrantless residential arrest. See Hudson, 547 U.S. at 593. It
relied on Miller and Sabbath as well. See id. at 594.
9
   Before Hudson, the Seventh Circuit had likewise concluded that the
exclusionary rule does not apply to knock-and-announce violations, see
United States v. Langford, 314 F.3d 892, 894–95 (7th Cir. 2002), and had
extended that holding to the arrest-warrant context, see United States v.
                                   12
declined invitations to limit Hudson to its facts. See, e.g.,
Smith, 526 F.3d at 311 (“Nor, contrary to [the defendant’s]
suggestion, does Hudson apply only when the officers have a
search warrant. . . . [T]he interests served by the knock-and-
announce rule . . . ‘have nothing to do with the seizure of the
evidence,’ and nothing to do with whether the Fourth
Amendment required the officers to obtain a warrant. There
is nothing about the presence of a warrant that increases the
value of deterring knock-and-announce violations, which the
Court tells us ‘is not worth a lot,’ or that mitigates the
‘substantial social costs’ of suppressing the evidence.”
(citations omitted)); Ankeny, 502 F.3d at 835–36 (“[W]e
decline to limit Hudson so narrowly to its facts. The Supreme
Court made it clear that, because the knock-and-announce
rule protects interests that ‘have nothing to do with the seizure
of . . . evidence, the exclusionary rule is inapplicable’ to
knock-and-announce violations.”).

     Moreover, we do not interpret Hudson on a blank slate.
As discussed, in Southerland, we considered whether Hudson
overruled two Supreme Court cases—Miller and Sabbath—
both of which involved knock-and-announce violations in the
arrest context. In Miller and Sabbath, the police officers
arrested the defendants in their respective residences without
an arrest warrant and without complying with the knock-and-
announce requirement. See Sabbath, 391 U.S. at 586–87;
Miller, 357 U.S. at 303–04. The Supreme Court held in both
cases that the knock-and-announce violations required

Smith, 171 F. App’x 516, 519 (7th Cir. 2006). It has apparently not
departed from this position post–Hudson. See Evans v. Poskon, 603 F.3d
362, 364 (7th Cir. 2010) (“The exclusionary rule is used in only a subset
of all constitutional violations—and excessive force in making an arrest or
seizure is not a basis for the exclusion of evidence. . . . Cf. Hudson v.
Michigan, 547 U.S. 586 (2006) (violation of constitutional knock-and-
announce rule does not justify exclusion).” (one citation omitted)).
                              13
suppression of the evidence found inside. See Sabbath, 391
U.S. at 586; Miller, 357 U.S. at 314. In Southerland,
however, we concluded that Hudson not only governed these
arrest cases—it overruled them. See Southerland, 466 F.3d at
1085–86. Southerland therefore held, directly contrary to my
colleagues’ position here, that Hudson cannot be read as
governing search warrants only. And Miller and Sabbath are
no “obstacle” to my position, Maj. Op. 21, because, according
to the Court, they were overruled by Hudson.                 See
Southerland, 466 F.3d at 1085–86. Although a distinction
could be drawn between a warrantless arrest (Miller and
Sabbath) and the execution of an arrest warrant (this case),
the distinction undercuts my colleagues’ position. If, as we
said in Southerland, the exclusionary rule does not apply to a
knock-and-announce violation when the police have no arrest
warrant, then it plainly is inapplicable when the police have
one. See Keiningham v. United States, 287 F.2d 126, 129
(D.C. Cir. 1960) (“[I]t is inconceivable that less should be
required of an officer acting without a warrant than is required
of him under a valid warrant.”).          In sum, I believe
Southerland’s interpretation of Hudson’s scope directly
refutes the search/arrest distinction my colleagues draw.
Southerland’s analysis was not dicta and it was unanimously
endorsed by the full Court via Irons footnote; accordingly, we
should follow it here. See United States v. Emor, 785 F.3d
671, 682 (D.C. Cir. 2015) (“[W]e cannot overrule a prior
panel’s decision, except via an Irons footnote or en banc
review.”).

                  B. HUDSON’S REASONING

    Even if Hudson did not directly control this case (on its
own terms and as interpreted in Southerland), its reasoning
applies with equal force to the arrest-warrant context. The
Hudson Court deemed the exclusionary rule inapplicable to
                             14
knock-and-announce violations on two alternative grounds:
attenuation and cost-benefit balancing. Both grounds are
holdings and so Weaver and my colleagues must successfully
distinguish them both. See Woods v. Interstate Realty Co.,
337 U.S. 535, 537 (1949) (“[W]here a decision rests on two or
more grounds, none can be relegated to the category of obiter
dictum.”). In my view, they successfully distinguish neither.

                      i. Attenuation

     Weaver spends most of his brief explaining why here,
unlike in Hudson, the knock-and-announce violation was the
but-for cause of the discovery of the evidence. His argument
goes as follows:
    •   Because the ATF officers violated the knock-
        and-announce requirement, Weaver did not have
        an opportunity to surrender himself at the door.
    •   Because Weaver did not surrender himself at the
        door, the officers forced their way inside.
    •   Because they were inside Weaver’s apartment,
        the officers were able to see the marijuana in
        plain view.
    •   Based on their plain-view observations, the
        officers obtained a search warrant.
    •   In executing the search warrant, the officers
        obtained the evidence ultimately used to convict
        Weaver.
Stated in reverse, Weaver believes the search warrant was
invalid because the plain-view observations were invalid
because the entry was invalid because the police did not
knock and announce.
                                   15
     Even assuming Weaver’s causation theory is correct, he
is wrong to suggest that the absence of but-for causation is the
“core” of Hudson. Appellant’s Br. 21. On the contrary, the
absence of but-for causation comprised all of two sentences of
the Court’s opinion. See Hudson, 547 U.S. at 592. Indeed,
the Hudson Court expressly downplayed the significance of
but-for causation. See id. (“Our cases show that but-for
causality is only a necessary, not a sufficient, condition for
suppression.”); id. (“[E]xclusion may not be premised on the
mere fact that a constitutional violation was a ‘but-for’ cause
of obtaining evidence.” (emphasis added)); id. (“[E]ven if the
illegal entry here could be characterized as a but-for cause of
discovering what was inside, we have never held that
evidence is fruit of the poisonous tree simply because it would
not have come to light but for the illegal actions of the
police.” (emphasis added) (quotation marks omitted)); id.
(“[B]ut-for cause, or causation in the logical sense alone, can
be too attenuated to justify exclusion.” (quotation marks and
citation omitted)); id. at 593 (“Attenuation . . . occurs when,
even given a direct causal connection, the interest protected by
the constitutional guarantee that has been violated would not
be served by suppression of the evidence obtained.”
(emphasis added)). 10 The real core of Hudson’s attenuation

10
    At times, my colleagues appear to agree with Weaver that Hudson was
primarily about the absence of but-for causation. See Maj. Op. 3–4, 10.
They emphasize Justice Kennedy’s concurrence, in which he said “the
failure to wait at the door cannot properly be described as having caused
the discovery of evidence.” Hudson, 547 U.S. at 604 (Kennedy, J.,
concurring in part and concurring in judgment). His concurrence
ultimately does not support their view, however, as he also stated more
broadly that suppression is unwarranted in the “context of the knock-and-
announce requirement” writ large. Id. at 603; see also id. at 604
(“[E]xtension [of the exclusionary rule to knock-and-announce violations]
also would have significant practical implications, adding to the list of
issues requiring resolution at the criminal trial questions such as whether
police officers entered a home after waiting 10 seconds or 20.” (emphasis
                                   16
analysis is the conclusion that “[t]he interests protected by the
knock-and-announce requirement . . . do not include the
shielding of potential evidence from the government’s eyes.”
Id. The interests that the knock-and-announce requirement
does protect—safety, property and dignity—“have nothing to
do with the seizure of the evidence.” Id. at 594. 11


added)). More importantly, he fully joined “Parts I through III” of the
majority opinion in Hudson (the attenuation and cost-benefit balancing
holdings). See id. at 604. As a lower court, we are bound to follow the
Supreme Court’s majority opinion, not the concurrence of a single Justice.
See Hansford v. United States, 303 F.2d 219, 225 (D.C. Cir. 1962) (en
banc); see also United States v. Duvall, 740 F.3d 604, 610 (D.C. Cir.
2013) (Kavanaugh, J., concurring in denial of rehearing en banc)
(“Justices who join the majority may of course express additional thoughts
in a concurrence, but concurrences do not bind lower courts in cases
where there is a majority opinion.”). Ultimately, my colleagues agree that
we must “employ Hudson’s legal framework in considering whether the
exclusionary remedy is appropriate here,” including its attenuation and
cost-benefit balancing holdings. Maj. Op. 12.
11
    My colleagues suggest that the Hudson Court limited its attenuation
analysis to the search-warrant context in noting that “the knock-and-
announce rule has never protected . . . one’s interest in preventing the
government from seeing or taking evidence described in a warrant.” 547
U.S. at 594 (emphasis added). Elsewhere, however, the Court made the
same point without any “search warrant” limitation. See id. at 593 (“The
interests protected by the knock-and-announce requirement . . . do not
include the shielding of potential evidence from the government’s eyes.”);
accord Smith, 526 F.3d at 311 (“Nor, contrary to [defendant’s] suggestion,
does Hudson apply only when the officers have a search warrant. The
explanations given by Hudson are not confined to situations in which the
officers violate the knock-and-announce rule after obtaining a
warrant . . . .”). As one commentator puts it:
      Hudson’s holding [cannot be confined] to “evidence described
      in a warrant” . . . . The purposes of the knock-and-announce
      rule identified by the Court . . . did not include shielding
      undescribed items from the authorities. Surely, this was no
      oversight and is more telling than the limiting language used to
      describe what the rule does not safeguard. The explanation for
                                  17
     Weaver contends, and my colleagues agree, that the
knock-and-announce requirement protects another interest:
the privacy interest in keeping the police out of one’s home.
See Maj. Op. 15–20. The dissent in Hudson made precisely
the same argument. See 547 U.S. at 620–21 (Breyer, J.,
dissenting) (“[The majority] does not fully describe the
constitutional values, purposes, and objectives underlying the
knock-and-announce requirement. That rule . . . [also]
protects the occupants’ privacy by assuring them that
government agents will not enter their home without
complying with those requirements . . . .”). Yet, according to
the Hudson majority, the only “privacy” interests protected by
the knock-and-announce requirement are “those elements . . .
that can be destroyed by a sudden entrance,” i.e., the ability to
“get out of bed,” “pull on clothes” and “prepare . . . for the
entry of the police.” Id. at 594 (majority op.); see also id. at
593 (“[C]ases excluding the fruits of unlawful warrantless
searches say nothing about the appropriateness of exclusion to
vindicate the interests protected by the knock-and-announce
requirement. . . . The interests protected by the knock-and-
announce requirement are quite different.” (citing, inter alia,
Weeks, 232 U.S. 383; Mapp, 367 U.S. 643) (emphasis
added)). As a lower court, we are not free to contradict the
Supreme Court’s exhaustive description of the interests
protected by the knock-and-announce requirement. See
Winslow v. FERC, 587 F.3d 1133, 1135 (D.C. Cir. 2009)

    the Court’s reference to “evidence described in a warrant” may
    well be that the evidence in Hudson was of that variety. In any
    event, it is inconceivable that the majority would have ordered
    suppression of the gun if the officers had possessed a warrant
    only for contraband narcotics and had seized the firearm in
    ‘plain view’ during a lawful search. And the cost-benefit
    balance struck in Hudson would be no different for evidence
    that had not been specified in a search warrant.
Tomkovicz, supra, at 1840 & n.105 (citation and some footnotes omitted).
                              18
(“Vertical stare decisis—both in letter and in spirit—is a
critical aspect of our hierarchical Judiciary headed by ‘one
supreme Court.’ ” (quoting U.S. CONST., art. III, § 1)).

     Of course, the arrest-warrant requirements—that a
warrant be issued by a neutral magistrate based on probable
cause and that the police have reason to believe the suspect is
present at the described locale, Payton v. New York, 445 U.S.
573, 602–03 (1980)—protect the privacy interest that Weaver
identifies. See id. at 589–90. But he concedes that those
requirements were complied with here. See Appellant’s
Reply Br. 5 n.2. The ATF officers had a valid arrest warrant
and therefore had the right to enter Weaver’s apartment to
effectuate his arrest. See Payton, 445 U.S. at 602–03. The
knock-and-announce violation he identifies, standing alone,
does not implicate his privacy interest in keeping the police at
bay from his residence and, thus, suppression would not
vindicate it. See Hudson, 547 U.S. at 593; see also United
States v. Ceccolini, 435 U.S. 268, 279 (1978) (for
exclusionary rule to apply, “[t]he penalties visited upon the
Government, and in turn upon the public, because its officers
have violated the law must bear some relation to the purposes
which the law is to serve”). And arrest-warrant requirements,
like search-warrant requirements, are sufficient to protect the
privacy interest my colleagues identify. See Payton, 445 U.S.
at 602–03 (“[A]n arrest warrant requirement may afford less
protection than a search warrant requirement, but it will
suffice to interpose the magistrate’s determination of probable
cause between the zealous officer and the citizen. If there is
sufficient evidence of a citizen’s participation in a felony to
persuade a judicial officer that his arrest is justified, it is
constitutionally reasonable to require him to open his doors to
the officers of the law.”); Summers, 452 U.S. at 704 (same).
In sum, Hudson’s attenuation analysis exempts from the
                              19
exclusionary rule a knock-and-announce violation committed
during the execution of an arrest warrant.

                      ii. Balancing Test

     Even if Hudson’s attenuation analysis were limited to
search warrants, the Court’s balancing-test analysis is
assuredly not. The Hudson Court concluded that the social
costs of applying the exclusionary rule to knock-and-
announce violations far exceed the deterrence benefits. See
547 U.S. at 599. This Court is not free to recalibrate the
scales. See Seminole Tribe of Fla. v. Florida, 517 U.S. 44, 67
(1996) (“When an opinion issues for the Court, it is not only
the result but also those portions of the opinion necessary to
that result by which we are bound.”). Faithfully adhering to
Hudson’s cost-benefit analysis, I think the exclusionary rule
plainly does not apply to arrest warrants as well. Indeed, the
Hudson Court’s balancing analysis in no way relied on the
existence vel non of a search warrant.

     The costs identified in Hudson are exactly the same here.
In both the search-warrant and arrest-warrant contexts,
suppression will “releas[e] dangerous criminals into society”
by excluding “relevant incriminating evidence.” Hudson, 547
U.S. at 595. It will also drain judicial resources by
“generat[ing] a constant flood of alleged failures to observe
the [knock-and-announce] rule,” which claims require
“extensive litigation” over “difficult,” fact-specific inquiries
like “what constituted a ‘reasonable wait time’ ” and whether
an exception to the knock-and-announce requirement applied.
Id.; see also id. at 589–90 (explaining that knock-and-
announce requirement “is not easily applied” and that “it is
not easy to determine precisely what officers must do”). And,
in both contexts, the “massive” consequences of suppression
will encourage police officers to “wait longer than the law
                              20
requires,” causing “preventable violence against officers” and
“the destruction of evidence.” Id. at 595. Indeed, Weaver
never contends otherwise.

     My colleagues claim that applying the exclusionary rule
in the arrest-warrant context will not trigger a flood of
burdensome litigation because “officers rarely violate the
knock-and-announce rule.” Maj. Op. 29. But they miss the
point made in Hudson. Whether or not a knock-and-announce
violation in fact occurs, every criminal defendant will claim it
did because “[t]he cost of entering this lottery would be small,
but the jackpot enormous: suppression of all evidence,
amounting in many cases to a get-out-of-jail-free card.”
Hudson, 547 U.S. at 595. Thus, in every case in which the
police find evidence during execution of an arrest warrant, the
defendant can and will claim that they violated the knock-
and-announce requirement by, for example, not waiting long
enough before entering. See id. It is the mere allegation of a
knock-and-announce violation, regardless whether it
ultimately has merit, that will require “extensive litigation”
via suppression hearings. Id. And the burdens on the
judiciary in adjudicating these claims will be even greater
than usual:

    Unlike the warrant or Miranda requirements,
    compliance with which is readily determined (either
    there was or was not a warrant; either the Miranda
    warning was given, or it was not), what constituted a
    “reasonable wait time” in a particular case (or, for
    that matter, how many seconds the police in fact
    waited), or whether there was “reasonable suspicion”
    of the sort that would invoke [an] exception[ to the
    knock-and-announce requirement], is difficult for the
    trial court to determine and even more difficult for
    an appellate court to review.
                              21
Id. At bottom, my colleagues argue with, rather than
distinguish, the High Court’s analysis in Hudson.

    My colleagues’ decision will also endanger law-
enforcement officers in the same way that Hudson predicted.
The point made in Hudson is not that the exclusionary rule
will deter police officers from violating the knock-and-
announce requirement but that it will lead to over-deterrence:

    Another consequence of the incongruent remedy [of
    applying the exclusionary rule to knock-and-
    announce violations] would be police officers’
    refraining from timely entry after knocking and
    announcing. As we have observed, the amount of
    time they must wait is necessarily uncertain. If the
    consequences of running afoul of the rule were so
    massive, officers would be inclined to wait longer
    than the law requires—producing preventable
    violence against officers . . . .

Id. (citation omitted). After today, this risk and uncertainty
will confront every police officer who executes an arrest
warrant in the District of Columbia.

     No matter the costs identified in Hudson, my colleagues
ultimately believe they are outweighed by an alleged increase
in deterrence benefits in the arrest-warrant context. See Maj.
Op. 27–29. Weaver contends, and my colleagues agree, that
police officers have a greater incentive to violate the knock-
and-announce requirement when executing arrest warrants
than search warrants: if officers can enter straightaway, they
can search the suspect’s residence more broadly than they
otherwise could. But “the value of deterrence depends upon
the strength of the incentive to commit the forbidden act” and,
as the Hudson Court reminds us, “deterrence of knock-and-
announce violations is not worth a lot.” 547 U.S. at 596.
                              22
Officers can already bypass the knock-and-announce
requirement if they have a “reasonable suspicion” that the
occupant will destroy evidence or violently resist arrest. Id.
Moreover, once they arrest the occupant, the police can search
his person and the areas within his reach, see In re Sealed
Case 96-3167, 153 F.3d 759, 767 (D.C. Cir. 1998), and
conduct a protective sweep of the home and seize any
incriminating evidence in plain view, see Maryland v. Buie,
494 U.S. 325, 334 (1990). These searches, in turn, will often
produce the probable cause necessary to obtain a full-blown
search warrant.

     My colleagues believe the protective sweep authorized by
the Fourth Amendment is more “limited” than it in fact is.
Maj. Op. 17. In the course of a residential arrest, officers can
“look[] in closets and other spaces immediately adjoining the
place of arrest from which an attack could be immediately
launched” without any probable cause or reasonable
suspicion. United States v. Ford, 56 F.3d 265, 269 (D.C. Cir.
1995) (quoting Buie, 494 U.S. at 334); see also United States
v. Thomas, 429 F.3d 282, 287 (D.C. Cir. 2005) (Buie
authorizes suspicionless sweep of “the entirety of a small
apartment”). The officers can also sweep more broadly
through the residence if they have a reasonable suspicion that
dangerous confederates may be present, see Buie, 494 U.S. at
334—a common suspicion when arresting a suspected drug
dealer like Weaver, see United States v. Cash, 378 F.3d 745,
749 (8th Cir. 2004) (“[A]n officer arresting a suspected drug
trafficker . . . is justified in conducting a Buie sweep out of
concern that there could be individuals lurking in the other
rooms who may resort to violence to thwart the arrest.”).
Most importantly, this latter type of sweep allows officers to
go inside the residence even if the arrestee surrenders outside
the door. See United States v. Henry, 48 F.3d 1282, 1284
(D.C. Cir. 1995) (Buie authorizes protective sweep of
                               23
residence even though “the police arrested the defendant
outside rather than inside his dwelling”).

      According to Weaver, however, the police cannot
conduct a protective sweep if the suspect surrenders himself
at the door—something he has no opportunity to do when the
police violate the knock-and-announce requirement. But see
Thomas, 429 F.3d at 287; Henry, 48 F.3d at 1284. Yet, the
notion that the police will forego knocking and announcing
just to broaden their search authority defies common sense.
Officers no doubt prefer the subject of an arrest warrant—a
suspected felon, mind you—to voluntarily surrender at the
door: breaking in and surprising him risks a life-threatening
struggle inside.      See Miller, 357 U.S. at 313 n.12
(“Compliance [with the knock-and-announce requirement] is
. . . a safeguard for the police themselves who might be
mistaken for prowlers and be shot down by a fearful
householder.”); Sabbath, 391 U.S. at 589 (“[T]he rule of
announcement . . . safeguard[s] officers, who might be
mistaken, upon an unannounced intrusion into a home, for
someone with no right to be there.”). Tellingly, Weaver cites
no evidence that police officers routinely violate the knock-
and-announce requirement during the execution of arrest
warrants. Cf. Hudson, 547 U.S. at 599 (“[P]olice forces
across the United States take the constitutional rights of
citizens seriously. There have been wide-ranging reforms in
the education, training, and supervision of police officers. . . .
[M]odern police forces are staffed with professionals.”
(quotation marks omitted)). Indeed, my colleagues appear to
agree that knock-and-announce violations during the
execution of arrest warrants will be “rare[],” with or without
the exclusionary rule. Maj. Op. 29. What is it, then, that
needs to be deterred? Cf. Herring, 555 U.S. at 147–48
(emphasizing absence of “systemic error” because “the
deterrent effect of suppression must be substantial,” not
                                    24
“marginal”); Hudson, 547 U.S. at 604 (Kennedy, J.,
concurring in part and concurring in judgment) (suppression
is inappropriate due to absence of “any demonstrated pattern
of knock-and-announce violations” (emphasis added)). 12

     Even if there were a greater need for deterrence in the
arrest-warrant context, my colleagues make no attempt to
explain why the “massive deterrence” of the exclusionary rule
is required, given the availability of potential civil liability
and internal police discipline. Hudson, 547 U.S. at 596. If a
federal law-enforcement officer violates the knock-and-
announce requirement while executing an arrest warrant, the
arrestee may file a Bivens action against him. See id. at 597.
Public-interest lawyers would be willing to handle the suit, id.
at 598; the suit would be worthwhile given the availability of
attorney’s fees, id. at 597; and the officer-defendants would
not be entitled to qualified immunity, id. at 598. According to
Hudson, we must “assume[]” that “civil liability is an
effective deterrent.” Id. Likewise, we must “assume” that
“internal police discipline” is an adequate deterrent as well.
Id. at 598–99. Police departments have an incentive to train
their officers to follow the knock-and-announce rule in order
to avoid municipal liability, id. at 599, and police officers
have an incentive to comply for the sake of their careers, id.

    In sum, the deterrence benefit of applying the
exclusionary rule to knock-and-announce violations is not

12
   Elsewhere, my colleagues claim “[t]he facts of this case” demonstrate
that officers will strategically violate the knock-and-announce requirement
to broaden their search authority. Maj. Op. 28. Even assuming a single
anecdote can ever be evidence of a larger trend, Weaver has not alleged at
any stage of this litigation that the ATF officers failed to announce their
purpose (“We have a warrant”) in order to gain entry to his apartment. In
fact, the officers knocked, announced their authority (“Police”) and waited
before attempting to enter—actions that make little sense if their purpose
was to catch Weaver by surprise.
                                25
meaningfully greater in the arrest context than in the search
context. At most, my colleagues have demonstrated that the
deterrence benefit of suppression could be somewhat higher in
the arrest-warrant context. This does not go far enough. The
1960s are over and we are no longer in the “heydays” of the
exclusionary rule. Id. at 597. The rule is a “last resort” and
there is a strong presumption against its application. Id. at
591; Davis, 131 S. Ct. at 2427. The mere “existence” of
deterrence benefits is “not . . . a sufficient condition” for
suppression. Hudson, 547 U.S. at 596; see also Calandra,
414 U.S. at 350 (“[I]t does not follow that the Fourth
Amendment requires adoption of every proposal that might
deter police misconduct.”); Leon, 468 U.S. at 910 (same).
Instead, “the deterrence benefits of suppression must
outweigh its heavy costs,” Davis, 131 S. Ct. at 2427
(emphasis added)—a condition the Supreme Court almost
never finds satisfied. See supra p.7 (collecting cases). In
Hudson, the Court did not say that the balance was close: it
said the social costs are “considerable,” the incentive to
violate the knock-and-announce requirement “minimal” and
the preexisting deterrences “substantial.” 547 U.S. at 599.
My colleagues may have added a pebble to one side of the
scale but they have ignored the boulder on the other side.
Applying the exclusionary rule to knock-and-announce
violations in the arrest-warrant context will drain judicial
resources, let guilty criminals go free and risk the lives of
police officers. See id. at 595. Compared to these
“substantial social costs,” id. at 596, the possibility that police
officers will enter homes without knocking to prevent
occupants from surrendering at the door—a risk that is neither
proven nor plausible—is trivial. Even if this worst-case
scenario is theoretically possible, the “incremental” benefit
gained from deterring it does not justify the blunderbuss
remedy of suppression. Harris, 495 U.S. at 20. Instead, the
cost-benefit analysis performed in Hudson renders the
                             26
exclusionary rule inapplicable to knock-and-announce
violations that occur during the execution of search warrants
and arrest warrants alike.



     For the foregoing reasons, Hudson v. Michigan governs
this case. I would affirm the district court’s denial of
Weaver’s motion to suppress and, accordingly, I respectfully
dissent.
