                               PUBLISHED

                    UNITED STATES COURT OF APPEALS
                        FOR THE FOURTH CIRCUIT


                              No. 12-4625


UNITED STATES OF AMERICA,

                  Plaintiff – Appellee,

           v.

HENRY STEPHENS,

                  Defendant – Appellant.



Appeal from the United States District Court for the District of
Maryland, at Baltimore.      James K. Bredar, District Judge.
(1:11-cr-00447-JKB-1)


Argued:   October 30, 2013                  Decided:   August 19, 2014


Before SHEDD and THACKER, Circuit Judges, and HAMILTON, Senior
Circuit Judge.


Affirmed by published opinion.  Judge Shedd wrote the majority
opinion, in which Senior Judge Hamilton joined.  Judge Thacker
wrote a dissenting opinion.


ARGUED: Christopher Ford Cowan, LAW OFFICE OF CHRIS F. COWAN,
Columbus, Ohio, for Appellant. Albert David Copperthite, OFFICE
OF THE UNITED STATES ATTORNEY, Baltimore, Maryland, for
Appellee. ON BRIEF: Rod J. Rosenstein, United States Attorney,
OFFICE OF THE UNITED STATES ATTORNEY, Baltimore, Maryland, for
Appellee.
SHEDD, Circuit Judge:

     Convicted            of    illegal      firearm      possession,       Henry         Stephens

contends that the district court erroneously denied his pretrial

motion to suppress evidence. Caselaw decided after Stephens was

indicted       tends       to    establish        that     the   search         at    issue       is

unreasonable         under      the    Fourth     Amendment,        but    we   are       not    now

concerned      with       the    legality       of   the    search.       Rather,         we    must

decide     the      separate          issue    of    whether        the     district           court

correctly declined to apply the exclusionary rule because the

search was conducted in “good faith.” Our consideration of this

issue    requires          us    to    answer     “the     objectively          ascertainable

question whether a reasonably well trained officer would have

known    that       the    search      was    illegal      in    light     of     all      of   the

circumstances.”           Herring       v.    United      States,    555    U.S.      135,       145

(2009) (citation and internal punctuation omitted). Because we

find that the search was “conducted in objectively reasonable

reliance       on    binding          appellate      precedent,”          Davis      v.     United

States,    131      S.Ct.       2419,     2423-24      (2011),      the    answer         to    this

question is “yes.” Therefore, the exclusionary rule does not

apply, and we affirm Stephens’ conviction.

                                                I

     The underlying facts are not disputed. In 2011, federal and

state    law     enforcement           officers      in    the    Baltimore          area       were

investigating Stephens for possible drug and firearms crimes.

                                                2
The investigation began as a result of information provided by a

registered   confidential   informant,        and   it   was   spearheaded       by

Officer Paul Geare, who was a 13-year veteran of the Baltimore

Police Department. Officer Geare was also deputized as an ATF

agent and assigned to a “High Intensity Drug Trafficking Area”

(“HIDTA”) task force unit, which was “a hybrid unit of federal

agents as well as city police officers” operating pursuant to

Baltimore City and HIDTA guidelines. J.A. 405. The HIDTA joint

task force is “organized to conduct investigations into drug and

gun   violations    of   both   federal       and     state    law,     and     its

investigations     indeed   [lead]       to    both      federal      and     state

prosecutions, determined on the basis of the facts uncovered.”

United States v. Claridy, 601 F.3d 276, 283 (4th Cir.), cert.

denied, 131 S.Ct. 259 (2010) (emphasis in original).

      On May 13, 2011, Officer Geare – acting without a warrant -

installed    a   battery-powered     Global-Positioning-System               device

(“GPS”) under the rear bumper of Stephens’ vehicle, which was

parked in a public lot in Parkville, Maryland. 1 Officer Geare had

information that Stephens was a convicted felon, that he would

be working security at a nightclub known as “Club Unite” on the


      1
        In March 2011, Officer Geare installed the                          GPS on
Stephens’ vehicle without a warrant, and it remained                         on the
vehicle for several weeks. Officer Geare testified that                     the GPS
probably had been removed because the battery was getting                   low.



                                     3
evening of May 16, and that he usually carried a firearm when he

worked    there.     With         this     knowledge,          Officer        Geare   –    in

conjunction with other officers - implemented a plan to detain

Stephens and search him on May 16 at Club Unite.

       During the evening of May 16, Officer Geare used the GPS to

locate Stephens’ vehicle at an area school. Officer Geare and

another city police officer (Sergeant Johnson) then observed and

followed Stephens          as    he    drove       the   vehicle    to    his    residence.

Before    Stephens    left       the     residence       to    drive     to    Club   Unite,

Officer    Geare     and        Sergeant    Johnson        saw      Stephens,     who     was

standing outside his vehicle, reach around to the back of his

waistband. They interpreted this movement as being a check for a

weapon. Based on this and other information they had previously

obtained, the officers “had at least reasonable suspicion, if

not probable cause, that [Stephens] was armed and was on his way

to work at Club Unite.” J.A. 520.

       When Stephens drove away from his residence, Officer Geare

alerted other officers who had been briefed on the plan to go to

Club   Unite.   Using       visual       observation          and   a    portable     laptop

computer to monitor the GPS, Officer Geare and Sergeant Johnson

followed Stephens’ vehicle as he drove on public roads to Club

Unite. Upon Stephens’ arrival at Club Unite, the officers who

had been alerted approached him and conducted a patdown, which

revealed an empty holster in the middle of his back. Within a

                                               4
matter of minutes, a Baltimore city police officer arrived and

conducted a canine inspection of the vehicle exterior. After the

canine    alerted,        the     officers        searched         the     vehicle        and   found

(among other things) a loaded pistol. The officers then arrested

Stephens and         charged       him    with        one    or    more       state-law      crimes.

Stephens       remained      in      state     custody            for    approximately          three

months, until         a   federal         grand       jury    indicted         him    for    illegal

firearm       possession        by    a    convicted          felon.       See       18   U.S.C.    §

922(g)(1). After the federal indictment, the state charges were

dismissed. See Presentence Report, No. JKB-11-0447, at 1 (D.

Md.). 2

      While this case was pending below, the Supreme Court held

in United States v. Jones, 132 S.Ct. 945, 949 (2012), that the

government’s         “installation           of       a     GPS    device       on    a     target’s

vehicle, and its use of that device to monitor the vehicle’s

movements, constitutes a ‘search’” within the meaning of the

Fourth Amendment. Because the officers in Jones did not have a

valid warrant authorizing the GPS usage, the search – i.e., GPS

usage     –   violated       the      Fourth      Amendment.            The    Court      did    not,

however,      rule    that      all    warrantless            GPS       searches      violate     the


      2
       The record does not specify the state charges for which
Stephens was arrested. We note, however, that possession of a
firearm by a convicted felon is a crime under § 5-133 of the
Maryland Public Safety Article.



                                                  5
Fourth    Amendment;         instead,      the      Court      expressly          declined    to

decide     whether     reasonable         suspicion         or    probable         cause     may

justify warrantless GPS attachment to vehicles, and that remains

an open question. Id. at 954.

      Based on Jones, Stephens moved to suppress the firearm and

other    evidence      seized      on    May       16.   Following       a    hearing,       the

district court denied the motion. The court concluded that in

light of Jones, Officer Geare’s warrantless use of the GPS on

Stephens’ vehicle was an unconstitutional search that led to the

seizure of the challenged evidence. However, the court held that

the exclusionary rule does not apply because Officer Geare used

the     GPS    in     good     faith.      Thereafter,           Stephens          entered     a

conditional        guilty    plea,      reserving        the     right       to    appeal    the

suppression order. See Fed. R. Crim. P. 11(a)(2).

                                            II

      In May 2011, at the time of Stephens’ arrest and before

Jones    was   decided,       it   was    not       uncommon      for    law       enforcement

officers      in    Maryland    to      attach      tracking      devices         to   vehicles

without a warrant. See J.A. 364. Indeed, caselaw in our circuit

shows that officers in Maryland had been doing so since at least

1976. See United States v. Woodward, 546 F.2d 576 (4th Cir.

1976) (declining to address the defendant’s argument that the

warrantless attachment of a “beeper” to his truck was an illegal

search     under      the    Fourth       Amendment).          Before        Officer       Geare

                                               6
attached the GPS to Stephens’ vehicle, he had attached a GPS to

other vehicles in public areas without a warrant, and it was his

understanding that a warrant was needed only when (unlike here)

the GPS was wired into the vehicle’s battery system. See J.A.

364-65.       Consistent          with     Officer      Geare’s      understanding,         the

district judge – who had been a United States Magistrate Judge

in Maryland for 12 years before being elevated to the district

court bench - observed that had Officer Geare applied for a

federal warrant to attach a GPS to Stephens’ vehicle, it was

“quite likely” that “the magistrate judge would have said . . .

you don’t need a warrant for that.” J.A. 454. As we explain

below, Officer Geare’s and the district judge’s understanding of

the state of the law as it existed in 2011 is understandable.

        The Fourth Amendment provides in relevant part that “[t]he

right    of    the       people    to     be   secure       in   their     persons,    houses,

papers, and effects, against unreasonable searches and seizures,

shall not be violated.” The “threshold question” in every Fourth

Amendment case is whether a search or seizure occurred, and “not

every observation made by a law enforcement officer – even if

consciously intended to disclose evidence of criminal activity –

constitutes          a    search         within       the     meaning      of    the   Fourth

Amendment.” United States v. Taylor, 90 F.3d 903, 908 (4th Cir.

1996). Rather, a search occurs for constitutional purposes only

“when    an    expectation         of     privacy      that      society    is   prepared    to

                                                  7
consider reasonable is infringed,” United States v. Jacobsen,

466 U.S. 109, 113 (1984), and “[o]fficial conduct that does not

compromise any legitimate interest in privacy is not a search

subject to the Fourth Amendment,” Illinois v. Caballes, 543 U.S.

405,   408    (2005)   (citation     and        internal   punctuation    omitted).

Under this principle, “[w]hat a person knowingly exposes to the

public . . . is not a subject of Fourth Amendment protection.”

Katz v. United States, 389 U.S. 347, 351 (1967).

       It was well-established by 2011 that “one’s expectation of

privacy in an automobile and of freedom in its operation are

significantly       different      from    the       traditional   expectation    of

privacy      and   freedom    in    one’s       residence.”    United    States   v.

Martinez-Fuerte, 428 U.S. 543, 561 (1976). In accord with this

principle, we recognized in United States v. George, 971 F.2d

1113, 1119 (4th Cir. 1992), that “there can be no reasonable

expectation of privacy in a vehicle’s exterior.” Moreover, we

observed in United States v. Gastiaburo, 16 F.3d 582, 586 (4th

Cir.    1994),      that     “it    may         be   reasonable    and    therefore

constitutional to search a movable vehicle without a warrant,

even though it would be unreasonable and unconstitutional to

conduct a similar search of a home, store, or other fixed piece

of property.” Further, we noted in United States v. Bellina, 665

F.2d 1335, 1340 (4th Cir. 1981), that “this rule of diminished



                                            8
expectation       of    privacy     is     particularly              appropriate         when   the

automobile is located in the street or in a public area.”

     Although          neither     the   Supreme          Court        nor    this    Court      had

expressly approved or disapproved of warrantless GPS usage in

2011,     the    Supreme       Court     had        rejected           a     Fourth      Amendment

challenge to law enforcement officers’ use of a beeper, which is

the technological forerunner to the GPS. In United States v.

Knotts, 460 U.S. 276 (1983), officers had placed a beeper in a

container       that    was    later     filled       with       chloroform,          which     they

suspected       was    being     used    to     make       illegal         drugs.     After      the

chloroform       was    purchased,       one        suspect          (Petschen)       placed     the

container       in     his    vehicle,        and     the        officers         followed       the

container by using both visual surveillance of the vehicle and a

monitor    that       received     signals         from        the    beeper.     The    officers

eventually       obtained      a   search       warrant          for       Knotts’    cabin     and

premises, which is where the container was delivered, and they

discovered       a     drug-making       laboratory.             Following         his     arrest,

Knotts     unsuccessfully          moved      to     suppress          evidence       on    Fourth

Amendment       grounds       because      of       the    beeper          use,    and     he    was

convicted on a drug conspiracy charge.

     The    Court       upheld     the   denial           of    the    suppression         motion,

holding that the use of the beeper was not a search under the

Fourth Amendment. Id. at 285. Noting the diminished expectation

of privacy in automobiles, the Court explained that “[a] person

                                                9
traveling     in    an   automobile         on    public    thoroughfares         has    no

reasonable    expectation        of    privacy      in    his   movements        from   one

place to another.” Id. at 281. Thus, “[w]hen Petschen travelled

over the public streets he voluntarily conveyed to anyone who

wanted to look the fact that he was travelling over particular

roads in a particular direction, the fact of whatever stops he

made, and the fact of his final destination. . . .” Id. at 281-

82.   Importantly,         the    Court      specifically            rejected     Knotts’

argument concerning the beeper:

      Visual   surveillance   from    public  places   along
      Petschen’s route or adjoining Knotts’ premises would
      have sufficed to reveal all of these facts to the
      police. The fact that the officers in this case relied
      not only on visual surveillance, but on the use of the
      beeper to signal the presence of Petschen’s automobile
      to the police receiver, does not alter the situation.
      Nothing in the Fourth Amendment prohibited the police
      from augmenting the sensory faculties bestowed upon
      them at birth with such enhancement as science and
      technology afforded them in this case.

Id. at 282. Although the Court left open the possibility that a

different rule may apply in a future case for “dragnet-type law

enforcement    practices,”        it    observed      that      to    the   extent      that

Knotts’ argument was “simply that scientific devices such as the

beeper    enabled    the    police     to    be    more    effective        in   detecting

crime, it simply has no constitutional foundation.” Id. at 284. 3


      3
       We upheld the constitutionality of technology-enhanced
extended surveillance of public areas in United States v.
Vankesteren, 553 F.3d 286 (4th Cir.), cert. denied, 556 U.S.
(Continued)
                                            10
      Knotts involved the use of a beeper, but it “was widely and

reasonably      understood       to    stand      for    the   proposition        that    the

Fourth    Amendment      simply        was     not       implicated       by    electronic

surveillance of public automotive movements.” United States v.

Sparks, 711 F.3d 58, 67 (1st Cir. 2013); see also United States

v. Aguiar, 737 F.3d 251, 261 (2d Cir. 2013) (“Knotts stood for

the proposition that the warrantless use of a tracking device to

monitor   the      movements     of    a   vehicle        on   public     roads    did    not

violate      the    Fourth   Amendment.”).              Although     we   had     not    been

presented with the issue directly, we interpreted Knotts, in

conjunction with the subsequent case of United States v. Karo,

468   U.S.    705    (1984), 4    as    standing         for   the    proposition        that




1269 (2009), where the defendant sought to exclude evidence
obtained by the government’s use of a hidden, motion-activated
video camera recording his open field. We noted that the “idea
of a video camera constantly recording activities on one’s
property is undoubtedly unsettling to some,” but government
agents could have personally monitored the area over a
continuous period without violating the Fourth Amendment, and
the fact that they “chose to use a more resource-efficient
surveillance method [did] not change our Fourth Amendment
analysis.” Id. at 291.
      4
       In Karo, government agents installed a beeper inside a
container and used the beeper to track the movement of the
container to various locations, including a number of private
residences. The Court agreed that using the beeper to monitor
the movement of the container within private residences violated
the Fourth Amendment. The Court distinguished Knotts because the
beeper was used in that case only to locate the container as it
traveled on public roads.



                                             11
“monitoring of a beeper falls within the ambit of the Fourth

Amendment when it reveals a critical fact about the interior of

premises   that    could   not   have      been   obtained      through   visual

surveillance.” United States v. Jones, 31 F.3d 1304, 1310 (4th

Cir. 1994) (citation and internal punctuation omitted).

     Moreover,    Knotts   was   considered       to    be    the   “foundational

Supreme Court precedent for GPS-related cases.” United States v.

Cuevas-Perez,     640   F.3d   272,   273    (7th      Cir.   2011).    Based   on

Knotts, several federal appellate courts held before 2011 that

the warrantless use of a GPS to track the location of a vehicle

did not necessarily violate the Fourth Amendment. See, e.g.,

United States v. Pineda-Moreno, 591 F.3d 1212, 1215-17 (9th Cir.

2010) (GPS installation and use is not a search); 5 United States

v. Marquez, 605 F.3d 604, 610 (8th Cir. 2010) (GPS installation

and use requires only reasonable suspicion); United States v.

Garcia, 474 F.3d 994, 997-98 (7th Cir. 2007) (GPS installation

and use is not a search); but see United States v. Maynard, 615

F.3d 544, 555-60 (D.C. Cir. 2010) (prolonged GPS surveillance is

a search). 6 Two months after Stephens was arrested, the Fifth


     5
       Both Pineda-Moreno and Cuevas-Perez were later vacated and
remanded for further consideration in light of the Supreme
Court’s 2012 Jones decision. See 132 S.Ct. 1533-34 (2012).
     6
       In August 2010, the United States Department of Justice
issued an internal email opining that Maynard was “fundamentally
wrong  and   incompatible  with  established   Fourth  Amendment
(Continued)
                                      12
Circuit relied on Knotts and its own prior precedent relating to

beeper usage to hold that the warrantless placement and usage of

a GPS on a vehicle was not a search under the Fourth Amendment.

See United States v. Hernandez, 647 F.3d 216, 220-21 (5th Cir.

2011).   Thus,     a     significant         body      of    federal       law    existed

nationally    in   2011       to     support         the    view    that     warrantless

attachment of a GPS to a vehicle was not a search within the

meaning of the Fourth Amendment or was permissible when officers

possessed reasonable suspicion that criminal activity was afoot. 7

     Consistent        with   this    body      of    federal      law,    the   Court   of

Special Appeals of Maryland had expressly found in 2008 that

warrantless      GPS     usage       was     permissible           under    the    Fourth

Amendment. In Stone v. State, 941 A.2d 1238 (Md. App. 2008),

Maryland law enforcement officers who were investigating Stone

for burglary attached a GPS to his truck, and they later used

information from the GPS to locate and arrest him. During a




principles.” See United States v. Wilford, 2013 WL 6211741, at
*39 (D. Md. 2013) (quoting the email).
     7
       Courts also applied Knotts in cases involving similar
surveillance methods. For example, in United States v. Forest,
355 F.3d 942 (6th Cir. 2004), agents monitored cell phone site
data to track the defendant’s movements along a public highway.
The court held that the defendant “had no legitimate expectation
of privacy in his movements along public highways,” and
therefore the agents did not conduct a search within the meaning
of the Fourth Amendment. Id. at 951.



                                           13
pretrial suppression hearing, Stone’s counsel sought to cross-

examine   one   of   the     officers      concerning      the    GPS   in   order    to

establish    that    the     GPS   usage    violated       his    Fourth     Amendment

rights. The trial court disallowed the cross-examination, and

Stone appealed.

      Relying primarily on Knotts, the Court of Special Appeals

affirmed the trial court, concluding that it “did not abuse its

discretion   in     cutting    short    the      appellant’s      cross-examination

about . . . the GPS tracking device because it was unlikely that

cross-examination       on    those     points        would   have      produced     any

relevant evidence.” Id. at 1249. The court noted that the GPS

was   “simply     the   next       generation         of   tracking     science      and

technology from the radio transmitter ‘beeper’ in Knotts, to

which the Knotts Fourth Amendment analysis directly applies,”

and it stated that “the use of the GPS device could not be a

Fourth Amendment violation, and hence further inquiry about it

[on   cross-examination]           would        not    have      led    to    relevant

information.” Id. at 1250. Explaining this decision, the court

observed:

      [Stone] did not have a reasonable expectation of
      privacy in his location in the public, and, more
      specifically, in a vehicle riding on public roads, and
      therefore evidence about the use of the GPS device . .
      . merely to locate him in public, which just as well
      could have been done by human visualization — though
      less efficiently — was not relevant to [his] Fourth
      Amendment-based suppression motion.


                                           14
Id. at 1250-51.

     Recently, in Kelly v. State, 82 A.3d 205, (Md. 2013), the

Maryland Court of Appeals resolved any doubt about the state of

the law that existed in Maryland in 2011. The court held that

“before Jones, binding appellate precedent in Maryland, namely

Knotts,   authorized       the    GPS    tracking      of    a    vehicle    on    public

roads.” Id. at 216. The court explained that before Jones, it

would have applied Knotts like the Court of Special Appeals had

done in Stone, “to resolve the question of the constitutionality

of GPS tracking of a vehicle on public roads.” Id.                               For this

reason,   the     court    held    that       “just   as    the    Court    of    Special

Appeals     applied       Knotts,       pre-Jones,         when     considering       the

relevance    of   testimony       on    the    subject      of    GPS   tracking    of   a

vehicle on public streets in Stone, so too could police officers

reasonably rely on Knotts, pre-Jones, in affixing a GPS tracking

device to the vehicle of a person under their investigation for

the purpose of conducting surveillance.” Id.

                                          III

     For purposes of this appeal, we accept the district court’s

ruling that Officer Geare’s use of the GPS to locate and follow

Stephens in May 2011 was an unreasonable search under the Fourth

Amendment that led directly to the seizure of the evidence from

Stephens’ vehicle and his arrest. Starting from this premise, we

must decide the separate question of whether the exclusionary

                                          15
rule renders the evidence inadmissible. 8 Because the facts are

not disputed, this question involves a pure legal conclusion,

and we review the district court’s ruling de novo. See United

States v. DeQuasie, 373 F.3d 509, 520 (4th Cir. 2004).

                                            A.

      The       Supreme     Court    created      the    exclusionary         rule    “to

safeguard against future violations of Fourth Amendment rights

through the rule’s general deterrent effect.” Arizona v. Evans,

514     U.S.     1,    10   (1995).     The      exclusionary     rule        “generally

prohibits        the   introduction         at   criminal      trial     of    evidence

obtained in violation of a defendant’s Fourth Amendment rights,”

Pennsylvania Bd. of Prob. & Parole v. Scott, 524 U.S. 357, 359

(1998), but the “sole purpose” of the rule “is to deter future

Fourth Amendment violations,” Davis v. United States, 131 S.Ct.

2419,     2426    (2011),     and     its    application       “properly      has     been

restricted to those situations in which its remedial purpose is

effectively       advanced,”       Illinois      v.   Krull,   480     U.S.    340,    347

(1987). As the Court has recently made clear, the exclusionary

rule is not a “strict liability regime,” Davis, 131 S.Ct. at

2429,     and    exclusion    of    evidence      has   “always   been     [the]      last


      8
       We decline to address the government’s argument that
Officer Geare’s use of the GPS was permissible under the
reasonable suspicion standard because the government conceded
below the illegality of the search under Jones. See J.A. 448-50.



                                            16
resort, not [the] first impulse.” Hudson v. Michigan, 547 U.S.

586, 591 (2006).

       “Exclusion exacts a heavy toll on both the judicial system

and society at large,” because it “almost always requires courts

to ignore reliable, trustworthy evidence bearing on guilt or

innocence,” and “its bottom-line effect, in many cases, is to

suppress the truth and set the criminal loose in the community

without punishment.” Davis, 131 S.Ct. at 2427. In order for the

exclusionary rule “to be appropriate, the deterrence benefits of

suppression        must        outweigh       its    heavy    costs.”      Id.     “Police

practices trigger the harsh sanction of exclusion only when they

are    deliberate        enough       to    yield     meaningful      deterrence,      and

culpable    enough        to    be    worth    the    price    paid   by   the     justice

system.”     Id.     at        2428     (citation      and     internal     punctuation

omitted). Therefore, the exclusionary rule is applicable “[w]hen

the police exhibit deliberate, reckless, or grossly negligent

disregard for Fourth Amendment rights, [and] the deterrent value

of    exclusion     is    strong      and     tends   to     outweigh   the      resulting

costs.”     Id.     at     2427       (citations       and     internal     punctuation

omitted).

       However,      “when        the      police     act     with    an    objectively

reasonable good-faith belief that their conduct is lawful, or

when their conduct involves only simple, isolated negligence,

the deterrence rationale loses much of its force, and exclusion

                                               17
cannot   pay    its    way.”    Id.    at    2427-28   (citations       and   internal

punctuation).         The     “pertinent         analysis    of      deterrence   and

culpability is objective, not an inquiry into the subjective

awareness of arresting officers,” and the “good-faith inquiry is

confined   to    the       objectively      ascertainable     question    whether    a

reasonably well trained officer would have known that the search

was illegal in light of all of the circumstances.” Herring, 555

U.S. at 145 (internal punctuation omitted). 9

     Conducting the good-faith inquiry, the Supreme Court has

found the exclusionary rule to be inapplicable in a variety of

circumstances involving Fourth Amendment violations. See, e.g.,

United   States       v.    Leon,     468    U.S.   897     (1984)    (where    police

conducted a search in reasonable reliance on a warrant that was

     9
       The good-faith inquiry is often referred to as the good-
faith “exception” to the exclusionary rule. However, given the
manner in which the Supreme Court has limited the application of
the exclusionary rule, some commentators have questioned the
accuracy of labeling the exclusionary rule as the “rule” and the
good-faith inquiry as the “exception.” See, e.g., Michael D.
Cicchini, An Economics Perspective on the Exclusionary Rule and
Deterrence, 75 Mo. L. Rev. 459, 462 (2010) (observing that
Herring “makes the exclusionary rule a misnomer; in fact, when
exclusion is treated as a last resort, it would be far more
accurate to label it the exclusionary exception rather than the
rule”); Matthew A. Josephson, To Exclude or Not To Exclude: The
Future of the Exclusionary Rule After Herring v. United States,
43 Creighton L. Rev. 175, 177 (2009) (“The Herring decision
could transform the exclusionary rule by making the exclusion of
evidence the exception rather than the rule when police violate
the Fourth Amendment.”).




                                            18
later held invalid); Krull (where police conducted a search in

reasonable reliance on subsequently invalidated state statutes);

Evans (where police reasonably relied on erroneous information

in a database maintained by judicial employees); Herring (where

police reasonably relied on erroneous information in a database

maintained by police employees). Our precedent makes it clear

that application of the good-faith inquiry is not limited to the

specific   circumstances       addressed     by   the   Supreme    Court.     For

example, in United States v. Davis, 690 F.3d 226, 251-57 (4th

Cir. 2012), cert. denied, 134 S.Ct. 52 (2013), we held that the

exclusionary rule did not apply where officers engaged in an

unconstitutional      search      by    extracting       and      testing     the

defendant’s DNA sample during a murder investigation without a

warrant. We explained that the Supreme Court’s “recent decisions

applying the exception have broadened its application, and lead

us to conclude that the Fourth Amendment violations here should

not   result   in   application   of   the    exclusionary     rule.”   Id.    at

251. 10




      10
        In Davis, the majority stated that it was faithfully
following Supreme Court precedent by applying “the rationale
supporting the Court’s application of the good-faith [inquiry],”
and it rejected the dissenting judge’s argument that it was
creating a “new, freestanding exception” to the exclusionary
rule. 690 F.3d at 256 n.34.



                                       19
                                           B.

      As we have noted, “the good-faith inquiry is confined to

the objectively ascertainable question whether a reasonably well

trained officer would have known that the search was illegal in

light of all of the circumstances.” Herring, 555 U.S. at 145

(citation      and    internal      punctuation        omitted).        In     Davis,    the

Supreme     Court       answered        this     question          in    one      specific

circumstance,        holding    that    “searches      conducted        in     objectively

reasonable      reliance       on   binding      appellate         precedent      are    not

subject to the exclusionary rule.” 131 S.Ct. at 2423-24. As the

Court explained: “An officer who conducts a search in reliance

on   binding    appellate       precedent       does    no    more      than     act    as   a

reasonable officer would and should act under the circumstances.

The deterrent effect of exclusion in such case can only be to

discourage      the    officer      from   doing       his    duty.”       Id.    at    2429

(citations and internal punctuation omitted). Thus, if “binding

appellate precedent” allowing warrantless GPS usage existed in

May 2011, and if it was objectively reasonable for a reasonably

well-trained        officer    to   rely    on    that       precedent,        then     Davis

controls, and the exclusionary rule is inapplicable.

      Despite the ample body of federal law existing in 2011 that

supported warrantless GPS usage similar to what happened in this

case, Stephens contends that none of those cases was binding

precedent      in    the   Fourth      Circuit    and,       for    that     reason,     the

                                           20
exclusionary rule must apply. In essence, Stephens relies on a

negative implication: in his view, the Davis Court’s application

of the good-faith inquiry in the specific circumstance where an

officer     has   reasonably       relied    on   binding     appellate    precedent

precludes application of the good-faith inquiry in the slightly

different context where an officer reasonably relied on non-

binding precedent, no matter how extensive and well-developed

that precedent may be.

     We have serious doubts about Stephens’ narrow view of the

good-faith inquiry. Nothing in Davis itself supports such an

interpretation.       Instead,         Davis       merely       establishes      the

inapplicability      of      the    exclusionary       rule     in   one   specific

circumstance. Davis does not, however, alter the general good-

faith     inquiry   which,    we    reiterate,      requires     consideration    of

whether a reasonably well-trained officer would have known that

a search was illegal in light of all of the circumstances. See

generally Leon, 468 U.S. at 918 (noting that “suppression of

evidence . . . should be ordered only on a case-by-case basis”).

Moreover, as noted, we have not previously limited the good-

faith     inquiry    only     to     the     precise    factual      circumstances

addressed by the Supreme Court. 11


     11
         A simple hypothetical highlights the weakness of
Stephens’ position. Returning to the days before the Supreme
Court decided Jones, we assume that every other federal
(Continued)
                                            21
     Stephens’   narrow   interpretation   of   Davis   presents   an

interesting issue, but one that is ultimately unnecessary for us

to decide. As we explain below, under the facts of this case the

rule announced in Davis directly controls: Officer Geare’s use

of the GPS was objectively reasonable because of the binding

appellate precedent of Knotts.

                                 C.

     In May 2011, before Jones, neither the Supreme Court nor

this Court had expressly approved or disapproved of warrantless

GPS usage. However, in 1983, the Supreme Court held in Knotts



appellate court in the country had found warrantless GPS usage
to be constitutional in published opinions, and we had done so
in an unpublished opinion. Under Stephens’ position, evidence
obtained by an officer in this circuit as a result of
warrantless GPS usage would have to be suppressed because
neither the out-of-circuit opinions nor our unpublished opinion
are binding appellate precedent. To accept that view, a court
would necessarily have to hold that even with this universal,
but non-binding, precedent that was directly on point, a
reasonably well-trained officer would have known that the search
was illegal in light of all of the circumstances.
     We also note that Stephens’ view appears to run counter to
the manner in which the Supreme Court has examined objective
reasonableness in the analogous context of qualified immunity.
See, e.g., Pearson v. Callahan, 555 U.S. 223, 244-45 (2009)
(“The officers here were entitled to rely on these cases, even
though their own Federal Circuit had not yet ruled on ‘consent-
once-removed’ entries. . . . Police officers are entitled to
rely on existing lower court cases without facing personal
liability for their actions.”); Wilson v. Layne, 526 U.S. 603,
617-18 (1999) (“Given such an undeveloped state of the law, the
officers in this case cannot have been expected to predict the
future course of constitutional law.” (citation and internal
punctuation omitted)).



                                 22
that the use of a beeper to track a vehicle was not a search

under the Fourth Amendment. In doing so, the Court explained

that    “[a]   person        traveling     in    an    automobile     on     public

thoroughfares has no reasonable expectation of privacy in his

movements from one place to another,” 460 U.S. at 281, and noted

that the beeper simply conveyed to the public what was evident

from visual surveillance.

       Knotts is not exactly on point with the facts of this case,

but it is the legal principle of Knotts, rather than the precise

factual    circumstances,        that    matters.      See   South    Dakota     v.

Opperman, 428 U.S. 364, 375 (1976) (noting that “in all Fourth

Amendment cases, we are obliged to look to all the facts and

circumstances of this case in light of the principles set forth

in . . . prior decisions”); United States v. LaBinia, 614 F.2d

1207, 1210 (9th Cir. 1980) (noting that “it is a general rule

that unless the Supreme Court expressly limits its opinion to

the facts before it, it is the principle which controls and not

the    specific     facts    upon    which      the   principle     was    decided”

(citation and internal punctuation omitted)). In this regard, we

reiterate that in conjunction with the general legal landscape

that existed before Jones, “Knotts was widely and reasonably

understood     to    stand     for   the      proposition    that    the     Fourth

Amendment simply was not implicated by electronic surveillance

of public automotive movements,” Sparks, 711 F.3d at 67, and it

                                         23
was the “foundational Supreme Court precedent for GPS-related

cases,” Cuevas-Perez, 640 F.3d at 273.

      After Jones, we know that such an interpretation of Knotts

is incorrect. Without the benefit of hindsight, however, and

with no contrary guidance from the Supreme Court or this Court,

we    believe   that       a    reasonably      well-trained   officer    in     this

Circuit could have relied on Knotts as permitting the type of

warrantless GPS usage in this case. See Aguiar, 737 F.3d at 262

(in declining to apply the exclusionary rule, the court stated

that “sufficient Supreme Court precedent existed at the time the

GPS   device    was    placed      for   the     officers   here   to    reasonably

conclude a warrant was not necessary in these circumstances”).

      Our decision extends to all law enforcement officers within

this Circuit as a matter of federal law, but it is bolstered in

this case by the Maryland Court of Appeals’ holding in Kelly

that Knotts was binding appellate precedent in Maryland under

Davis and, therefore, Maryland police officers could “reasonably

rely on Knotts, pre-Jones, in affixing a GPS tracking device to

the   vehicle    of    a       person   under    their   investigation     for    the

purpose of conducting surveillance.” Kelly, 82 A.3d at 216. 12 To


      12
        “[S]tate law is irrelevant for determining in the first
instance whether fruits of a search are admissible in federal
court under the Fourth Amendment, [but] state law is relevant
when the analysis proceeds to the question of admitting
unconstitutionally seized evidence under [the] good faith
(Continued)
                                           24
be sure, Officer Geare worked on the HIDTA task force and was

deputized as a federal agent, but he was also a Baltimore City

police     officer.        In      this     dual      role,        Officer       Geare   was

investigating         both        federal      and        state     crimes,       and    his

investigation        led   to     Stephens’       arrest     for    violating      Maryland

law. Under these circumstances, we would make a mockery of the

good-faith      inquiry      if    we   were   to     ignore       the   clear    pre-Jones

state     of   the   law   in     Maryland     –     as    pronounced     by     Maryland’s

highest court - and hold that a Maryland officer’s use of the

GPS was objectively unreasonable. The fact that Stephens was

later charged federally does not alter our determination. 13




exception to the exclusionary rule.” United States v. Maholy, 1
F.3d 718, 722 (8th Cir. 1993).
     13
        Stephens contends that the HIDTA investigation was
federal and that Maryland law is irrelevant. However, the facts
do not establish that the investigation was exclusively federal,
and our precedent regarding joint federal-state investigations
undercuts Stephens’ argument. As we have explained, when
“federal and state agencies cooperate and form a joint law-
enforcement effort, investigating violations of both federal and
state law, . . . [s]uch an investigation is conducted on behalf
of both sovereigns, and its object is to reveal evidence of
crime - be it federal crime or state crime.” Claridy, 601 F.3d
at 282. Moreover, “in the initial stages of a criminal
investigation, it may be anything but clear whether the conduct
being investigated violates state law, federal law, or both,”
United States v. Self, 132 F.3d 1039, 1043 (4th Cir. 1997), and
“the decision with respect to the court in which charges are to
be brought is often made by the Office of the United States
Attorney and the state prosecutor, not the investigating
officer,” Claridy, 601 F.3d at 282. Thus, the “possibility, even
likelihood, of the federal government also bringing charges for
(Continued)
                                             25
                                  IV

     Based on the foregoing, we find no basis to set aside the

order   denying   Stephens’   suppression   motion.   Accordingly,   we

affirm the conviction.

                                                              AFFIRMED




the same underlying facts as the original state arrest does not
suddenly cause state officers to stop performing their duties,”
United States v. Taylor, 240 F.3d 425, 428 (4th Cir. 2001), and
the fact that “federal officers were present, assisting in the
arrest of the defendant by the state officers and that they
cooperated with the state officers in the investigation that led
up to the arrests has never been held in any case to render the
state arrest federal,” United States v. Iaquinta, 674 F.2d 260,
268 (4th Cir. 1982) (emphasis in original).



                                  26
THACKER, Circuit Judge, dissenting:

           “When law enforcement officers rely on precedent to

resolve legal questions as to which ‘[r]easonable minds . . .

may differ,’ the exclusionary rule is well-tailored to hold them

accountable for their mistakes.”               United States v. Davis, 598

F.3d 1259, 1267 (11th Cir. 2010), aff’d, 131 S. Ct. 2419 (2011)

(quoting   United   States     v.    Leon,     468    U.S.    897,       914   (1984)).

Clearly then, the exclusionary rule is well-tailored to hold

accountable the law enforcement officers in this case who relied

on   non-binding,   non-precedential          authority      regarding         emerging

technology -- without first bothering to seek legal guidance --

in order to conduct a warrantless search which spanned a period

of nearly two months.

           Therefore, with all due respect to my colleagues in

the majority, I dissent.

                                        I.

           In   this   case,        federal     and    state       law    enforcement

officers   conducted   surveillance           to   track     the    whereabouts     of

Appellant’s vehicle via the installation of a global positioning

system (“GPS”) device.       The officers used a battery operated GPS

device affixed to the undercarriage of Appellant’s vehicle to

track his movements 24 hours a day, resulting in a catalog of

data detailing the vehicle’s location for nearly two months from



                                        27
March 20 to April 12, 2011, and again from May 13 to May 16,

2011.

             They       did    so   without       obtaining         a    search        warrant,

despite the fact that no urgent or exigent circumstance existed.

Indeed, in the words of one of the officers, “the investigation

was taking too long,” and officers “were spending too much time

dragging it out.” J.A. 374. 1

             They       did    so   without       consulting        the       United     States

Attorney’s      Office        regarding     the    legality      of       such    a    search,

despite the fact that there was no binding appellate precedent

authorizing their actions, and there was clear indication that

the law in this regard was not settled, but rather, in a state

of flux.

             Eight      months      later,       the   Supreme          Court    ruled    such

conduct to be in violation of the Fourth Amendment.                              On January

23,     2012,   the      Supreme         Court    ruled      that       the     Government’s

installation of a GPS device on the undercarriage of a target’s

vehicle while it was parked in a public parking lot, “and its

use     of   that       device      to    monitor      the     vehicle’s          movements,

constitute[d]       a    search”     under       the   Fourth       Amendment.           United

States v. Jones, 132 S. Ct. 945, 949 (2012) (internal quotation


      1
       Citations to the “J.A.” refer to the Joint Appendix filed
by the parties in this appeal.



                                             28
marks omitted).       In light of the Jones decision, the district

court invited Appellant to file a motion for reconsideration of

his motion to suppress, which the district court had initially

denied.   Ultimately, the district court ruled that, per Jones,

the use of the GPS tracking device in this case was illegal, but

the   officers     acted   in    good   faith,    and   the   purpose   of   the

exclusionary rule would not be advanced if the evidence were to

be suppressed. 2

                                        II.

           It is a fundamental tenet of the Fourth Amendment that

warrantless searches are per se unreasonable, “subject only to a

few   specifically    established       and    well-delineated    exceptions.”

Katz v. United States, 389 U.S. 347, 357 (1967).                  The text of

the   Fourth     Amendment      provides      protection   from   unreasonable

searches and seizures of “persons, houses, papers, and effects.”

U.S. Cont. amend. IV.           As the Supreme Court recognized, “[t]he




      2
        The Government conceded below the illegality of the
search.   J.A. 450-51 (“THE COURT:   And the use of the GPS was
illegal.    [GOVERNMENT COUNSEL]: And, yes, that is correct.
That’s what the Supreme Court has said.”).        Curiously, the
Government now attempts to reverse course before us and argue
that a warrant was not needed for the search because the
officers had a reasonable suspicion Appellant was engaged in
illegal activity. Appellee’s Br. 23 (“Installation and use of a
slap-on GPS tracking device is such a limited intrusion that it
should be justified based upon reasonable suspicion.”).



                                        29
text of the Fourth Amendment reflects its close connection to

property.”         United States v. Jones, 132 S. Ct. 945, 949 (2012).

               Although the Fourth Amendment protects the right to be

free    from       unreasonable       searches       and       seizures,    it    “is    silent

about how this right is to be enforced.                           To supplement the bare

text,       [the    Supreme]     Court    created          the    exclusionary        rule,   a

deterrent sanction that bars the prosecution from introducing

evidence       obtained    by     way    of    a     Fourth       Amendment       violation.”

Davis v. United States, 131 S. Ct. 2419, 2423 (2011).                                The Court

has repeatedly held that the exclusionary rule’s sole purpose

“is to deter future Fourth Amendment violations.”                                Id. at 2426.

Exclusion      of     evidence    collected          by    unconstitutional          means    is

“not    a    personal     constitutional            right,      nor    is   it   designed     to

redress the injury occasioned by an unconstitutional search.”

Id. (internal quotation marks omitted).                           Rather, it is designed

to safeguard the continued vitality of the Fourth Amendment.

               The    deterrent         function          of     the   exclusionary       rule

necessarily requires us to consider the “culpability of the law

enforcement          conduct     at     issue.            When     the      police      exhibit

deliberate, reckless, or grossly negligent disregard for Fourth

Amendment rights, the deterrent value of exclusion is strong and

tends to outweigh the resulting costs.”                            Davis, 131 S. Ct. at

2427        (internal     quotation           marks        and     citations         omitted).

Therefore, “[t]o trigger the exclusionary rule, police conduct

                                               30
must be sufficiently deliberate that exclusion can meaningfully

deter    it,    and     sufficiently        culpable      that   such       deterrence    is

worth the price paid by the justice system.”                         Herring v. United

States, 555 U.S. 135, 144 (2009).

               Based on this rationale, the Supreme Court created a

“good faith” exception to the exclusionary rule, which applies

when     law        enforcement       officers      “act      with       an    objectively

‘reasonable good-faith belief’ that their conduct is lawful.”

Davis, 131 S. Ct. at 2427 (quoting United States v. Leon, 468

U.S. 897, 909 (1984)).                 The Court has applied the good faith

exception to evidence obtained by law enforcement officers who

acted in objectively reasonable reliance upon a search warrant

issued    by    a     neutral     magistrate,       but      where    the     warrant    was

ultimately found to be unsupported by probable cause.                            See Leon,

468 U.S. at 909.              The Court also applied this exception when

officers       acted    in    objective        reliance      upon    a    state    statute

ultimately found to violate the Fourth Amendment.                             See Illinois

v. Krull, 480 U.S. 340 (1987).                  And in Davis, the Court further

articulated this exception applies “when the police conduct a

search in objectively reasonable reliance on binding appellate

precedent.”          131 S.Ct. at 2427.           None of these factual scenarios

are present here.

               In    Davis,     the    Court    ruled     this      exception     applies,

“when    the    police       conduct    a   search      in   objectively        reasonable

                                             31
reliance on binding appellate precedent.”                  Davis, 131 S. Ct. at

2434 (emphasis supplied).           In further explaining this holding,

the Court stated, “when binding appellate precedent specifically

authorizes a particular police practice, well-trained officers

will and should use that tool to fulfill their crime-detection

and public-safety responsibilities.”             Id. at 2429 (emphasis in

original).       Thus, Davis carves out a very specific and narrow

articulation of circumstances in which the good faith exception

to the exclusionary rule applies: when officers conduct a search

in   objectively       reasonable     reliance        on     binding     appellate

precedent     specifically     authorizing      their       conduct.      See    id.

Davis did not, however, answer “the markedly different question

whether the exclusionary rule applies when the law governing the

constitutionality of a particular search is unsettled.”                       Id. at

2435 (Sotomayor, J., concurring).

            When presented with the question below as to whether

the good faith exception applied in the circumstance presented

by this case, the district court denied Appellant’s motion to

suppress determining that “the purposes of the [e]xclusionary

[r]ule   would    just   not   be   achieved    in    any    way    whatsoever    if

suppression      was   ordered.”      J.A.     479.         The    district    court

determined that the conduct of the law enforcement officers was

in good faith and “passes muster.”             Id.      In so concluding, the

district court relied on United States v. Michael, 645 F.2d 252,

                                       32
257 (5th Cir. 1981) (en banc), and Krull, 480 U.S. 340, as proof

that       the        law     surrounding      the     nonconsensual,         warrantless

installation of an electronic tracking device was settled before

Jones, 132 S. Ct. 945.

                 In     Michael,       the     Fifth    Circuit        held    that      the

nonconsensual,              warrantless      installation    of    a    beeper    on     the

defendant’s van did not violate the Fourth Amendment even if it

was a search.               645 F.2d at 256.        In Krull, officers conducted a

warrantless search of an automobile wrecking yard pursuant to a

state statute authorizing warrantless administrative searches of

those licensed to sell motor vehicles or automotive parts.                               480

U.S. at 343.            The Supreme Court held that the exclusionary rule

did not apply to the evidence obtained by the search because the

officers acted in objectively reasonable reliance upon the state

statute,         even       though   that    statute   was   subsequently        found    to

violate the Fourth Amendment.                  Id. at 342.        In relying on these

two cases, the district court determined that beepers and GPS

devices were one and the same for purposes of Fourth Amendment

analysis. 3           Therefore, the district court concluded that the law


       3
        Specifically, when discussing the use of a GPS device
versus a beeper, the district court stated that GPS monitoring
“isn’t a new technology. This is old technology. It’s 20, 30,
40 years that police officers have been using beepers,
transponders, whatever you want to call them, and following them
around.    And it’s not a subject that the [c]ourts haven’t
previously addressed.”    J.A. 470.    As discussed more fully
(Continued)
                                               33
was settled and that investigators acted in good faith relying

on this settled law “when the beeper was placed on the bumper.”

J.A. 479.        There are three reasons, recognized in Davis, that

this analysis is flawed:         (1) at the time the warrantless search

was conducted in this case, no “binding appellate precedent”

existed     in    this    circuit      “specifically    authoriz[ing]”      law

enforcement’s actions, 131 S. Ct. 2429, 2434; (2) the law in

general regarding the warrantless use of GPS devices was not

settled, but was, in fact, in a state of flux; and (3) law

enforcement officers did not act in an “objectively reasonable”

manner, id. at 2429 (quoting Leon, 468 U.S. at 919).

                                        A.

            At the time the warrantless search was conducted in

this   case,     no   “binding   appellate    precedent”   existed   in   this

circuit “specifically authoriz[ing]” law enforcement’s actions,

Davis, 131 S. Ct. 2429, 2434.                The words “binding appellate

precedent” should be given their plain meaning.                 Id. at 2434.

Binding appellate precedent in this circuit means the published

opinions    of   this    court   and   the   United   States   Supreme   Court.

See, e.g., McBurney v. Young, 667 F.3d 454, 465 (4th Cir. 2012)




below, beepers and GPS devices are not one and the same.
Moreover, Krull, 480 U.S. 340, did not involve the use of a
beeper at all, let alone a GPS device.



                                        34
(“Appellants’ reliance on [a Third Circuit opinion] is misplaced

for at least two reasons.              First, as out-of-circuit authority,

it is not binding on this Court.”); Hogan v. Carter, 85 F.3d

1113, 1118 (4th Cir. 1996) (“[U]npublished opinions are not even

regarded as binding precedent in our circuit . . . .” (citing

Local     Rule   36(c))).          Simply   put,       opinions    of    other    circuit

courts of appeal in general and of the Fifth Circuit Court of

Appeals in particular -- such as Michael, 645 F.2d 252, upon

which the district court relied -- are not binding precedent in

the Fourth Circuit.

              Indeed,    it    is    uncontroverted         that   at    the     time    the

warrantless search in this case was conducted, the two appellate

courts that bind the District Court of Maryland -- this court

and     the   Supreme      Court      --    had        no   precedent      specifically

authorizing      the    warrantless        use    of    a   GPS   device    to    track      a

suspect’s        vehicle      or     even        authorizing       the     warrantless,

nonconsensual      installation        of    a    beeper     tracking      device       on   a

suspect’s vehicle. 4          The majority attempts to fill the void left


      4
       Even if such a case existed relative to beeper tracking
devices, I am doubtful installation of a beeper would also
“specifically authorize[]” installation of a GPS device. Davis,
313 S. Ct. at 2429.      The two are of an entirely different
character. A beeper tracking device requires law enforcement to
at least be in proximity to the device to receive the
transmitted signal, whereas a GPS device downloads location data
at specific time intervals with no proximity needed. See, e.g.,
Jones, 132 S. Ct. at 963-64 (Sotomayor, J., concurring)
(Continued)
                                            35
by this absence of binding precedent by describing instead what

it calls a “significant body of federal law” and precedent from

the Court of Special Appeals of Maryland and the Maryland Court

of Appeals supporting the warrantless attachment of a GPS to a

vehicle.      Ante   at   13.     But   the    majority    fails   to   cite   any

binding appellate precedent specifically authorizing the conduct

as required by Davis.            The majority focuses instead on United

States v. Knotts, 460 U.S. 276 (1983), and United States v.

Karo, 468 U.S. 705 (1984).              However, reliance on these cases

here is misplaced.         As discussed below, in both cases, Knotts

and Karo, the beeper was placed in a container with the consent

of   the   then-owner,     not   attached     to   the   undercarriage    of   the

suspect’s vehicle without knowledge or consent of the vehicle’s

owner.     Clearly, these cases do not “specifically authorize[]”

the nonconsensual, warrantless installation of a GPS device on a

suspect’s vehicle.        Davis, 131 S. Ct. at 2429.

            The majority also quotes our decision in United States

v. Jones, 31 F.3d 1304 (4th Cir. 1994), for the proposition that

we interpreted Knotts and Karo to exclude the use of a beeper

tracking device from “the ambit of the Fourth Amendment” unless



(discussing the differences between surveillance using a GPS
device and a beeper).    In other words, with the use of a GPS
device, law enforcement may simply download the data from afar
at their leisure, as they did in this case.



                                        36
“it reveals a critical fact about the interior of premises that

could not have been obtained through visual surveillance.”                               Ante

at 11-12 (quoting Jones, 31 F.3d at 1310 (internal quotation

marks    omitted)).       However,      reliance         on    this    case       is    also

misplaced.       In Jones, we were asked to determine “whether the

postal    inspectors’     use    of   an    electronic         tracking       device       to

monitor    the     contents     of    Jones’       van     constituted        a        search

forbidden by the Fourth Amendment.”                  Id. at 1309.         Relying on

Knotts and Karo, we concluded it was not a search because, as in

the Supreme Court cases, the beeper tracking device

            was not planted in the van; it was concealed
            in a mail pouch which belonged to the
            [G]overnment and in which Jones had no
            expectation of privacy whatsoever. The mail
            pouch with the beeper found its way into
            Jones’ van only because Jones stole the
            pouch and hid it in the van himself.

Id. at 1310.       We made sure to illustrate that the facts in Jones

did not “raise[] the disturbing specter of [G]overnment agents

hiding electronic devices in all sorts of personal property and

then following private citizens who own such property as they go

about their business,” as does the case before us now.                             Id. at

1311.      There    was   no     such      danger     in      Jones,    because          “the

[G]overnment      ha[d]   placed      the       electronic     device    in       its     own

property,” and “[o]nly purloiners of such property need fear

adverse consequences.”          Id.



                                           37
            Indeed, the Supreme Court’s discussion in Jones, 132

S. Ct. 945, of its own beeper cases forecloses the possibility

that these cases support the warrantless GPS search in the case

at hand.    In Jones, the Court identified a critical distinction

between its precedent regarding the use of beepers and the case

before the Court, which, as here, involved the nonconsensual,

warrantless   installation    of    a    GPS    device     on    the    suspect’s

vehicle.    Id. at 951-52.    The Supreme Court observed that in its

prior beeper cases, the beepers in question had initially been

placed in containers with the consent of the then-owner, and the

containers later came into the defendant’s possession.                    See id.

(discussing Knotts, 460 U.S. 276, and Karo, 468 U.S. 705); see

also United States v. Brown, 744 F.3d 474, 478 (7th Cir. 2014)

(deciding the good faith exception applied to the warrantless

installation of a GPS device on a vehicle “[b]ecause the GPS

unit that played a role in the gathering of evidence against

Brown was installed with the consent of the Jeep’s owner, Knotts

and Karo are ‘binding appellate precedent’”).                 Thus, the Supreme

Court   described   the   defendant      in    Jones     as     being   “on    much

different footing” than the Knotts and Karo defendants because

he actually possessed the vehicle at the time the Government

installed   the   GPS   tracker,   and   he    had   not      consented   to    its

installation.     132 S. Ct. at 952.           That is precisely the case

here.

                                    38
                                      B.

            The Government also argues that the law regarding GPS

searches was generally settled before the Supreme Court issued

its opinion, and therefore, the main purpose of the exclusionary

rule -- to deter future Fourth Amendment violations -- would not

be   met.        According     to   the    Government,      “[p]rior       to   the

installation of the GPS tracking devices in this case, the vast

majority of decisions had upheld the use of GPS tracking devices

without a warrant.”        Appellee’s Br. 29.

            First and foremost, Davis sets a higher bar than a

simple   survey    of   an    amorphous    “vast    majority   of   decisions.”

Appellee’s Br. 29.           Rather, objectively reasonable reliance on

binding appellate precedent specifically authorizing the conduct

at issue is the gauge.          Beyond this basic premise, the Supreme

Court’s decision in Jones further undermines the Government’s

argument.    The officers in Jones -- standing on the same pre-

Jones legal footing on which the officers in this case stood --

felt compelled to obtain a search warrant in order to attach a

GPS device to the target’s vehicle.               See 132 S. Ct. at 948.         In

2005, the officers in Jones, participating in a joint FBI and

Metropolitan      Police     Department    Task    Force,   applied    for      and

received a warrant from the United States District Court for the

District    of   Columbia      authorizing   the     installation     of    a   GPS

device on a suspect’s vehicle in the District of Columbia within

                                      39
ten days of the warrant’s issue.                Id.     However, they installed

the GPS device outside the restrictions found in the warrant

inasmuch as they installed the GPS device on the 11th day and in

Maryland, rather than in the District of Columbia.                          Id.    The

fact that pre-Jones other officers -- located right next door to

the officers in this case no less -- would feel the need to

secure a warrant before installing and using a GPS device on a

suspect’s       vehicle   certainly          casts     further      doubt     on   the

Government’s argument that an officer similarly positioned to

the officers here would have reasonably thought the warrantless

search    in    this   case    was    permissive       under   binding      appellate

precedent.

               To be sure, the Government correctly asserts the main

purpose   of     the   exclusionary     rule     is    to   deter    future    Fourth

Amendment violations, not to remedy past ones.                   But, it does not

then follow that the district court correctly found there was no

police misconduct in this case to be deterred because they acted

in conformity with legal norms that were, at the time, “widely

accepted.”        Appellee’s    Br.    12.      Mere    conformity     with    widely

accepted legal norms is not the standard, nor should it be.

Reliance on past practice in general in order to invade the

province of the Fourth Amendment without a firm legal basis is

not conscientious police work and is, at minimum, reckless.



                                         40
            Because      no   such   binding        authority   existed    in    this

circuit at the time of the execution of the warrantless search

in   this   case,    I   conclude      that    the    good    faith    exception    as

articulated in Davis is unsuitable here. 5                   Thus, I next turn to

whether the good faith exception can apply at all to the factual

circumstances       of   this   case    --     in    other   words,    whether     law

enforcement acted in an objectively reasonable manner.                     Critical

to this analysis is the fact that, contrary to the Government’s

assertion, the law in this area was not generally accepted or

“widely accepted,” but, rather, was in a state of flux; so much

so   that    the     Supreme     Court        had    accepted    the     issue     for

consideration.




      5
       See also, United States v. Martin, 712 F.3d 1080 (7th Cir.
2013) (per curiam).    Although the Seventh Circuit decided the
case on other grounds, it stated that the district court’s
reliance on Davis was “an unwarranted expansion of the Supreme
Court’s decision” because “[a]s Justice Sotomayor pointed out in
her opinion concurring in the judgment, Davis ‘d[id] not present
the markedly different question whether the exclusionary rule
applies when the law governing the constitutionality of a
particular search is unsettled.’”     Martin, 712 F.3d at 1082
(quoting Davis, 131 S. Ct. at 2435 (Sotomayor, J., concurring)).
The court emphasized that the good faith exception as pronounced
in Davis applies “only to ‘a search [conducted] in objectively
reasonable reliance on binding appellate precedent.’”         Id.
(quoting Davis, 131 S. Ct. at 2434) (emphasis in original).



                                         41
                                               C.

               Law enforcement officers in this case did not act in

an “objectively reasonable” manner, Davis at 2429 (quoting Leon,

468 U.S. at 919).           The good faith exception at its core requires

officers      to    “act    with    an    objectively       ‘reasonable          good-faith

belief’ that their conduct is lawful.”                       Davis, 131 S. Ct. at

2427 (quoting Leon, 468 U.S. at 909).                       The Supreme Court has

recognized,        “[r]esponsible        law-enforcement          officers       will    take

care to learn what is required of them under Fourth Amendment

precedent and will conform their conduct to these rules.”                                 Id.

at 2429 (internal quotation marks omitted).                            I conclude that,

here, the officers could not have had an objectively reasonable

belief that their conduct was lawful for several reasons.

              First,       at    the     time       the   warrantless         search      was

conducted      in    this       case,    the    District     of    Columbia        Circuit,

neighboring        the     District      of    Maryland    where        the     warrantless

search    here      occurred,      had    determined      that     a    warrantless       GPS

search    violated       the    Fourth     Amendment.        See       United    States    v.

Maynard, 615 F.3d 544, 549 (D.C. Cir. 2010), aff’d in part sub

nom. United States v. Jones, 132 S. Ct. 945 (2012).                             In fact, at

the   time    the    warrantless         search     was   conducted      in     this    case,

Maynard had been accepted for argument before the Supreme Court,

further      undercutting        the    Government’s      position       here     that    the

issue was generally settled.                    Additionally, the Maynard case

                                               42
illustrates that as early as 2005, similarly situated officers

were    obtaining      warrants   for      GPS   searches   such    as   the   one

performed in this case.           Nonetheless, officers in this case did

not “take care to learn” what was required of them by Fourth

Amendment precedent under these circumstances.                     Davis, 131 S.

Ct. at 2429.

             Quite the contrary. Detective Geare testified that he

did    not   seek    advice   from   any     legal   authority     regarding   the

constitutionality of such a search, even though there was no

exigent circumstance preventing him from doing so.                   Appellant’s

counsel questioned Detective Geare,

             Q    At any point did you call the U.S.
             Attorney’s Office and say, hey, I’m thinking
             about putting a GPS device on a vehicle
             without a warrant, should I get one, you
             never did that, did you?

             A   No, not to my recollection.

             Q   The U.S. Attorney they were available to
             you, correct?

             A      Sure.

             . . .

             Q   The person you would talk to if you had
             legal questions was the U.S. Attorney,
             correct?

             A   Correct.

             Q And you didn’t call them in reference to
             this issue?

             A   Correct.

                                        43
J.A. 422.       Instead, Detective Geare testified that in utilizing

the GPS device in this case, he relied simply on his own past

conduct using GPS devices in prior cases that had resulted in

convictions.          Detective     Geare      testified      that   it   was     his

“understanding” that a warrant was not required when attaching a

GPS device on a target’s vehicle, and his “belief” that as long

as the vehicle was in a public area attaching a GPS device “was

fine.”     J.A. 365.        He certainly did not receive such guidance

from the United States Attorney’s Office because, per his own

testimony, he did not bother to ask.

               Because law enforcement officers acted with reckless

disregard for Appellant’s Fourth Amendment rights and failed to

act reasonably to “learn what was required of them” under the

Fourth Amendment before conducting a warrantless search via the

use   of   a    GPS   tracking    device      to    monitor   Appellant’s       every

movement in his vehicle for a period spanning nearly two months,

I cannot conclude that they acted with an objectively reasonable

good faith belief that the warrantless GPS search was lawful.

Davis, 131 S. Ct.at 2429.

                                        III.
               In   light   of   this   era    of   fast-moving      technological

advancements and our ever-shrinking zone of privacy, see Riley

v. California, 134 S. Ct. 2473 (2014) (holding officers must



                                         44
obtain a warrant before searching a cell phone seized incident

to an arrest), 6 law enforcement officers should be deterred from

undertaking warrantless searches in situations where, as here,

there was no binding appellate precedent authorizing the action,

there was no exigent circumstance, and the state of the law was

unsettled.             The   Government      must   err    on   the   side   of   the

Constitution and obtain a warrant especially as “the disturbing

specter of [G]overnment agents hiding electronic devices in all

sorts of personal property and then following private citizens

who own such property as they go about their business” becomes

ever more possible.              United States v. Jones, 31 F.3d 1304, 1311

(4th Cir. 1994).             In the words of the Seventh Circuit, I “reject

the [G]overnment’s invitation to allow police officers to rely

on   a       diffuse    notion    of   the   weight   of   authority    around    the

country, especially where that amorphous opinion turns out to be




         6
       In Riley, the Supreme Court recognized that cell phones, a
relatively new technology “inconceivable just a few decades
ago,” “are now such a pervasive and insistent part of daily life
that the proverbial visitor from Mars might conclude they were
an important feature of human anatomy.”     134 S. Ct. at 2484.
The Court further stated, “[t]he fact that technology now allows
an individual to carry [private] information in his hand does
not make the information any less worthy of the protection for
which the Founders fought.” Id. at 2495. The Court recognized
that its decision “will have an impact on the ability of law
enforcement to combat crime;” however, it also emphasized that
“[p]rivacy comes at a cost.” Id. at 2493.



                                             45
incorrect   in   the   Supreme   Court’s   eyes.”   United   States   v.

Martin, 712 F.3d 1080, 1082 (7th Cir. 2013) (per curiam).

            I would reverse the judgment of the district court.




                                   46
