                               In the

    United States Court of Appeals
                 For the Seventh Circuit
                     ____________________
No. 14-3785
UNITED STATES OF AMERICA,
                                                   Plaintiff-Appellee,

                                 v.

EUGENE A. SWEENEY,
                                               Defendant-Appellant.
                     ____________________

         Appeal from the United States District Court for the
                   Eastern District of Wisconsin.
              No. 14-CR-20 — Lynn Adelman, Judge.
                     ____________________

    ARGUED SEPTEMBER 11, 2015 — DECIDED MAY 9, 2016
                     ____________________

   Before BAUER, WILLIAMS, and HAMILTON, Circuit Judges.
    HAMILTON, Circuit Judge. Defendant Eugene Sweeney used
a gun to rob a Milwaukee tavern where he had worked before.
He was convicted of armed robbery under the Hobbs Act, 18
U.S.C. § 1951(a), brandishing a firearm during a crime of vio-
lence, 18 U.S.C. § 924(c), and possessing a firearm as a felon,
18 U.S.C. § 922(g)(1). He was sentenced as an armed career
offender under 18 U.S.C. § 924(e). Sweeney appeals both his
convictions and his sentence. He asserts that the district court
2                                                  No. 14-3785

erred in denying his motion to suppress the firearm central to
all three convictions, which was seized in a warrantless search
of the common space in the basement of his apartment build-
ing. He also asserts his sentence is erroneous, both because
the district court did not state or support with findings all
conditions of supervised release and because he does not
qualify as an armed career criminal.
   We affirm the district court’s denial of the motion to sup-
press the firearm, so Sweeney’s convictions stand. Following
recent case law concerning supervised release, however, we
vacate Sweeney’s sentence and remand for re-sentencing. We
do not resolve Sweeney’s challenge to the armed career crim-
inal finding, which was first raised on appeal. That question
should be addressed on remand, where both sides may de-
velop a full record and the district court may consider
whether the disputed legal issue matters to Sweeney’s ulti-
mate sentence.
I. The Fourth Amendment Issue
    Sweeney’s challenge to his convictions requires us to ap-
ply the Fourth Amendment to the police search of a common
area of Sweeney’s apartment building. A police officer
searched the area without a warrant and found a handgun
that matched the victim’s description of the robber’s gun. We
review the facts and then explain why the search did not vio-
late Sweeney’s Fourth Amendment rights.
    A. The Robbery, Investigation, and Search
    On the morning of December 23, 2013, Melissa Baldus ar-
rived at her job as general manager of Flannery’s Pub in Mil-
waukee. She had a bank bag containing cash for the register.
She entered Flannery’s through an alleyway door and walked
No. 14-3785                                                   3

downstairs to her office. A man then entered through the
same door, came upon Baldus, drew a gun, and demanded
the money. Baldus turned over the bank bag. The robber fled,
and Baldus called the police. She offered a confident identifi-
cation of the robber as Eugene Sweeney: Sweeney had previ-
ously worked a few short stints at Flannery’s, and Baldus said
she recognized him from his gestures, body movements,
voice, and sunglasses. She also described the gun as black and
silver with a red dot on the side. After obtaining Sweeney’s
address from Flannery’s personnel records, three officers—
Detective Delgado, Officer Gasser, and Officer Wilcox—went
to Sweeney’s apartment.
    Details of the apartment building layout are relevant to the
Fourth Amendment analysis. The building contains six apart-
ments, two on each of three floors. Sweeney’s apartment was
on the second floor. The building has exterior doors at the
front and rear that are usually closed and locked. In the back
of the building is a common rear staircase that can be entered
from the back of each apartment. Those stairs lead down to
the first floor and on down to the basement.
    At the bottom of the basement stairs to the left is an open-
ing to a common area. Water heaters are lined up against the
wall that runs along the staircase. Past those is a small crawl
space underneath the stairs. To the right of the stairs is a
shared laundry facility for the building tenants. They make
frequent use of the laundry and often allow friends and neigh-
bors to use the laundry as well.
   When the police arrived looking for Sweeney, Officer Wil-
cox covered the rear door of the building. Detective Delgado
and Officer Gasser entered through the front door, which had
been propped open, and found Sweeney’s apartment. After
4                                                      No. 14-3785

they knocked, the door was eventually opened by Sweeney’s
girlfriend. While talking with her, the officers received a radio
call from Officer Wilcox saying he had caught Sweeney trying
to leave by the back door and taken him into custody. At that
point, with consent from Sweeney’s girlfriend, Detective Del-
gado entered and searched the apartment. Officer Gasser
went through the apartment, out its rear door, and down the
common rear staircase.
    Our focus is Officer Gasser’s search of the basement. He
went down the stairs to the basement and turned left. He
went past the water heaters to the crawl space under the
stairs. There he found a black plastic bag containing a hand-
gun, magazine, and ammunition. Ms. Baldus, the manager of
Flannery’s, later testified at trial that the handgun looked like
the one used in the robbery. In searches of the apartment,
Sweeney’s car, and Sweeney himself, none of which are chal-
lenged here, the officers also found money and a pair of sun-
glasses matching the description of the robber’s.
    B. The Motion to Suppress
    Sweeney moved to suppress the gun discovered in the
basement. After an evidentiary hearing, a magistrate judge
recommended suppression of the firearm. In light of the Su-
preme Court’s recent decisions in United States v. Jones, 132 S.
Ct. 945 (2012), and Florida v. Jardines, 133 S. Ct. 1409 (2013), the
judge concluded that Officer Gasser trespassed upon
Sweeney’s property in retrieving the gun and thus conducted
an unlawful search.
   The government sought review before District Judge
Adelman, who heard testimony from defense investigator
William Kohl, defendant Sweeney, Officer Gasser, and the
No. 14-3785                                                    5

owner of the apartment building. Sweeney testified that his
lease entitled him to use the basement, though he said he had
never before used the area to store personal property. When
the owner was questioned about tenants using the basement
for storage, however, he flatly replied that “there is no storage
in the basement. If we find there’s stuff in the basement, …
then we ask them to remove it and not to use the basement for
storage.” The owner also said the basement was common
space, associated with no apartment in particular. Judge
Adelman denied the motion to suppress. He found that the
basement search did not violate Sweeney’s Fourth Amend-
ment rights. At trial, the jury convicted Sweeney on all
charges.
   C. Analysis of the Fourth Amendment Search
    The Fourth Amendment provides: “The right of the peo-
ple to be secure in their persons, houses, papers, and effects,
against unreasonable searches and seizures, shall not be vio-
lated … .” The text of the Fourth Amendment “indicates with
some precision the places and things encompassed by its pro-
tections: persons, houses, papers, and effects.” Florida v.
Jardines, 569 U.S. —, 133 S. Ct. 1409, 1414 (2013) (citation and
quotation marks omitted); see also United States v. Jones, 565
U.S. —, 132 S. Ct. 945, 950 (2012) (Fourth Amendment ex-
presses “a particular concern for government trespass upon
the areas (‘persons, houses, papers, and effects’) it enumer-
ates”).
   Applying the Fourth Amendment to various common
spaces in apartment buildings has been a source of consider-
able controversy. In cases decided before Jardines, we held that
warrantless police intrusions into shared spaces in apartment
buildings much like the basement here did not violate the
6                                                    No. 14-3785

Fourth Amendment rights of tenants. United States v. Villegas,
495 F.3d 761, 767–68 (7th Cir. 2007) (internal duplex hallway);
United States v. Concepcion, 942 F.2d 1170, 1172 (7th Cir. 1991)
(shared entrance to apartment building); cf. United States v.
Boden, 854 F.2d 983, 990 (7th Cir. 1988) (common area of rental
storage unit facility). More recently, based on the intervening
Supreme Court decision in Jardines, we have held that bring-
ing a police dog to sniff for drugs outside an apartment door
amounts to a search of the apartment interior that requires a
warrant. United States v. Whitaker, — F.3d —, Nos. 14-3290, 14-
3506, 2016 WL 1426484, at *4 (7th Cir. April 12, 2016).
    Sweeney does not challenge any factual findings by the
district court, so we accept them, but we review the district
court’s legal conclusions de novo. See United States v. Richards,
741 F.3d 843, 847 (7th Cir. 2014), citing United States v. Huddle-
ston, 593 F.3d 596, 600 (7th Cir. 2010). We focus our attention
on Jardines, where the majority and concurring opinions re-
flect two principal approaches to the Fourth Amendment’s
protection. Each casts light on the warrantless search of the
apartment building basement here. We address first the ap-
proach focused on the common law of property and whether
the police committed a trespass when conducting the search.
See Jardines, 133 S. Ct. at 1413–18 (trespass to property); Jones,
132 S. Ct. at 949–54 (trespass to chattel). We then turn to the
second approach, focused on whether the person challenging
the search had a reasonable expectation of privacy in the lo-
cation that was searched. See Jardines, 133 S. Ct. at 1418–20
(Kagan, J., concurring); Jones, 132 S. Ct. at 957–64 (Alito, J.,
concurring in the judgment).
No. 14-3785                                                     7

       1. The Fourth Amendment and Trespass
    In recent years, the Supreme Court has revived a “prop-
erty-based approach” to identify unconstitutional searches.
Jones, 132 S. Ct. at 950; see also id. at 949 (“The text of the
Fourth Amendment reflects its close connection to property
… .”). Under this approach, where the government has “phys-
ically occupied private property for the purpose of obtaining
information,” its intrusion is a search subject to the Fourth
Amendment. Id. at 949. In Jones, police officers trespassed
upon an “effect”—a car—by attaching a GPS tracker to its
chassis. In Jardines, officers trespassed upon a “house”—a
home’s porch—by conducting a dog-sniff at the front door.
    To establish a Fourth Amendment violation under this ap-
proach, there must be some trespass upon one of the pro-
tected properties enumerated by the Constitution’s text. This
in turn requires courts to consider the scope of trespass at
common law. Jones, 132 S. Ct. at 949 (Fourth Amendment case
law historically “tied to common-law trespass”). Neither Jones
nor the common law provides sharp boundaries for the mean-
ing of trespass for our purposes. See Orin S. Kerr, The Curious
History of Fourth Amendment Searches, 2012 Sup. Ct. Rev. 67,
90–91 (2012) (“The term ‘trespass’ could be understood as em-
bracing a wide range of ideas.”); see also Kyllo v. United States,
533 U.S. 27, 31–32 (collecting cases that analyze meaning of
trespass in Fourth Amendment context). The Restatement ap-
proach to trespass is a good starting point. See Laurent Sa-
charoff, Constitutional Trespass, 81 Tenn. L. Rev. 877, 891 (2014)
(endorsing Restatement (Second) of Torts as best authority for
discerning meaning of trespass for Jones inquiry).
8                                                   No. 14-3785

    Under the relevant Restatement definition, trespass means
that one “enters land in the possession of the other.” Restate-
ment (Second) of Torts § 158 (Am. Law Inst. 1965); see also
Jones, 132 S. Ct. at 949, quoting Entick v. Carrington, 95 Eng.
Rep. 807, 817 (C.P. 1765), for the proposition that “no man can
set his foot upon his neighbour’s close without his leave; if he
does he is a trespasser, though he does no damage at all … .”
Possession means “occupancy of land with intent to control
it.” Restatement (Second) of Torts § 157. And occupancy
means to “manifest a claim of exclusive control of the land.”
Restatement (Second) of Torts § 157 cmt. a. Put together, then,
to prove a claim of trespass, one must have possession of the
property in question and the ability to exclude others from
entrance onto or interference with that property.
   Sweeney cannot show any trespass on his property. He did
not have any form of exclusive control over the basement. The
basement was a common space, used by a number of resi-
dents. His lease gave him no exclusive property interest in
any part of the area. It did not even give him the right to store
items there.
    Nor could Sweeney have excluded someone from the
basement. Suppose Sweeney had discovered a non-resident
taking shelter in the basement who refused to leave. He could
call his landlord for aid, but Sweeney himself could not sue
the intruder for civil trespass on his property. See State v.
Dumstrey, 859 N.W.2d 138, 144 (Wis. App. 2014), aff’d, 873
N.W.2d 502 (Wis. 2016), quoting State v. Nguyen, 841 N.W.2d
676, 681 (N.D. 2013), for the proposition that tenant has no
right to exclude “technical trespassers in the common hall-
ways” of apartment building.
No. 14-3785                                                      9

    Rather, as Judge Adelman explained, any such trespass
would be a trespass against the building owner, not against
any individual tenants. See, e.g., Aberdeen Apartments v. Cary
Campbell Realty Alliance, Inc., 820 N.E.2d 158, 166 (Ind. App.
2005) (collecting cases holding that landlord can sue for tres-
pass to common areas of multi-unit dwellings); Commonwealth
v. Thomas, 267 N.E.2d 489, 491 (Mass. 1971) (collecting cases
and affirming denial of motion to suppress under very similar
circumstances); Motchan v. STL Cablevision, Inc., 796 S.W.2d
896, 900 (Mo. App. 1990) (concluding that “a landlord, who
retains control of common areas in a multi-tenant building,
also retains possession of those areas so as to support an ac-
tion for trespass to the common areas”). Only the building
owner or landlord could bring suit, so only the owner or land-
lord could have objected to Officer Gasser’s warrantless
search of the crawl space under the stairs.
    Accordingly, even if Officer Gasser committed a trespass,
it was not Sweeney’s right under long-established tort law to
exclude him. But whether or not there was a trespass,
Sweeney also faces a separate obstacle: he cannot establish
that police set foot onto an area for which the Fourth Amend-
ment affords Sweeney protection.
    Not all trespasses by law enforcement are violations of the
Fourth Amendment. See Oliver v. United States, 466 U.S. 170,
183–84 (1984). For instance, under the “open fields” doctrine
an officer may search for evidence on private land not within
close proximity to a home on the property. Jardines, 133 S. Ct.
at 1414, citing Hester v. United States, 265 U.S. 57 (1924); Andree
v. Ashland County, 818 F.2d 1306, 1315 (7th Cir. 1987). To vio-
late the Fourth Amendment, the trespass must occur on a
10                                                    No. 14-3785

“constitutionally protected area”—that is, one explicitly enu-
merated in the text of the Fourth Amendment. Jardines, 133 S.
Ct. at 1414, quoting United States v. Knotts, 460 U.S. 276, 286
(1983) (Brennan, J., concurring). This includes the home,
which extends to the “curtilage” of the home as well. Id.
    The basement was not recognizable as curtilage of
Sweeney’s apartment. See United States v. Redmon, 138 F.3d
1109, 1128 (7th Cir. 1998) (en banc) (Evans, J., concurring) (“In
a multi-unit apartment building there may in fact be no curti-
lage except perhaps in a separate area—like a basement stor-
age locker—subject to one’s exclusive control.”). Other courts
have held, often categorically so, that common basements of
multi-unit buildings or closely related spaces are not part of
the individual units’ curtilage. United States v. Brooks, 645 F.3d
971, 975–76 (8th Cir. 2011) (staircase leading to shared base-
ment space in apartment building); United States v. King, 227
F.3d 732, 753 (6th Cir. 2000) (basement of a two-family dwell-
ing); United States v. Cruz Pagan, 537 F.2d 554, 558 (1st Cir.
1976) (common basement garage of condominium building);
Thomas, 267 N.E.2d at 491 (basement of three-story, six-unit
apartment building, containing common space with laundry
facilities); see also Carol A. Chase, Cops, Canines, and Curtilage:
What Jardines Teaches and What It Leaves Unanswered, 52 Hou-
ston L. Rev. 1289, 1303 (2015) (“Generally speaking, appellate
courts that have considered whether common areas in a
multi-family dwelling are part of the curtilage of a dwelling
have been reluctant to recognize curtilage protection for those
areas.”).
   It is not necessary to decide categorically here that the
basement of a multi-unit residential building is or is not al-
ways the curtilage of individual units. It is enough to say that
No. 14-3785                                                   11

it was not in this case. Curtilage is a common-law concept of-
ten defined in abstract terms. See Jardines, 133 S. Ct. at 1414–
15 (curtilage includes all of the “branches and appurtenants”
of the home), quoting 4 W. Blackstone, Commentaries on the
Laws of England 223, 225 (1769); id. at 1415 (curtilage is that
part of the property “intimately linked to the home, both
physically and psychologically”), quoting California v. Ciraolo,
476 U.S. 207, 213 (1986); United States v. French, 291 F.3d 945,
951 (7th Cir. 2002) (curtilage is the “area outside the home it-
self but so close to and intimately connected with the home
and the activities that normally go on there that it can reason-
ably be considered part of the home”), quoting Siebert v. Sev-
erino, 256 F.3d 648, 653–54 (7th Cir. 2001). At bottom, the un-
derlying test is practical. If the Fourth Amendment shields the
“right of a man to retreat into his own home” free from intru-
sion, then it must also protect against an officer “stand[ing] in
a home’s porch or side garden” like a bold snooper looking
for evidence or peering through the windows. Jardines, 133 S.
Ct. at 1414.
    In most cases it is easy to say what the curtilage is. See
Jardines, 133 S. Ct. at 1415. A porch, a small fenced-in yard, a
gated walkway along the side of a house—all are obviously
part of the curtilage. This common-sense understanding saves
courts, police officers, and citizens from needing to apply neb-
ulous, ad hoc, case-by-case standards with great uncertainty.
Oliver, 466 U.S. at 181–82; United States v. Redmon, 138 F.3d
1109, 1138 (7th Cir. 1998) (en banc) (Rovner, J., dissenting).
   When we encounter novel questions about the scope of
curtilage, we take into account the four Dunn factors: “(1) the
proximity of the area in question to the home; (2) whether the
area is included in an enclosure surrounding the home; (3)
12                                                   No. 14-3785

how the owner uses the area; and (4) the measures taken to
protect the area from observation.” Bleavins v. Bartels, 422 F.3d
445, 451 (7th Cir. 2005), citing United States v. Dunn, 480 U.S.
294, 301 (1987). In this case these factors show that the search
here did not occur in any curtilage of Sweeney’s apartment.
    First, proximity: the basement was remote from the sec-
ond-floor apartment, and Sweeney did not have a private
basement storage space that was searched. There was no con-
cern that officers might be able to prevent Sweeney from his
right to “retreat into his own home” or that they could other-
wise “observe his repose from just outside the front window.”
Jardines, 133 S. Ct. at 1414.
   Second, an enclosure surrounding the home: Sweeney ar-
gues that the basement was within the “enclosure” of the
apartment building’s walls, accessible only from within the in-
dividual apartments or by a locked rear door. Under Dunn,
though, the question is not whether the area at issue was
within the walls of the building, but whether it was enclosed
and intimate to Sweeney’s apartment itself. It was not.
    Third, the nature of the use: Sweeney had no particular
use of the basement that tied it to his own apartment. It served
primarily as a shared laundry facility and location for utilities
for all tenants. Sweeney did not use it for activities “intimately
linked” to his home.
   Fourth, measures taken to protect the basement from ob-
servation by the public: This factor is a little more favorable to
Sweeney. On one hand, as a basement space within a locked
apartment building, it was unlikely to be seen by a member of
the general public. On the other hand, there was no door to
No. 14-3785                                                     13

the basement itself once one was inside the back of the build-
ing, and tenants often allowed outsiders into the basement to
do laundry. There is no evidence that Sweeney himself took
affirmative steps to protect the basement area from observa-
tion. See State v. Dumstrey, 873 N.W.2d 502, 514 (Wis. 2016)
(noting, in context of apartment parking garage, the curtilage
inquiry “is not whether the [area] is generally shielded from
the public at large,” but rather whether the person “has taken
steps to shield the [area] from the view of passersby within
the [area]”). While this last factor gives Sweeney a little
ground for argument, when all factors are taken together, the
basement was not within the curtilage of Sweeney’s apart-
ment. The trespass or property-right theory for Fourth
Amendment protection did not give Sweeney any rights in
the basement crawl space.
       2. The Fourth Amendment and Expectations of Privacy
    Neither party contends that Sweeney had a reasonable ex-
pectation of privacy in the basement of the apartment build-
ing, but we address the issue briefly in light of our recent de-
cision in United States v. Whitaker, — F.3d —, Nos. 14-3290, 14-
3506, 2016 WL 1426484 (7th Cir. April 12, 2016). As the district
court noted, there is generally no reasonable expectation of
privacy in shared and common areas in multiple-dwelling
residential buildings. Harney v. City of Chicago, 702 F.3d 916,
925 (7th Cir. 2012) (walkway adjacent to condominium build-
ing but behind gate), citing, for instance, United States v. Ville-
gas, 495 F.3d 761, 767–68 (7th Cir. 2007) (internal duplex hall-
way); see also United States v. Dillard, 438 F.3d 675, 683 (6th
Cir. 2006) (collecting cases from circuit courts establishing
lack of reasonable expectation of privacy in common areas of
apartment buildings).
14                                                  No. 14-3785

     Here, where the basement space was “shared by all of the
tenants” of the apartment building, see Harney, 702 F.3d at
925, there was no individualized storage space and no door or
locked entry to the basement itself, it was not objectively rea-
sonable that the space would be assumed private. This is true
even though the exterior door of the building was locked to
exclude persons who are not tenants of the building; the crit-
ical factor is that multiple tenants could enter and use the
space. Id.
    This reasoning does not mean that law enforcement can
freely use common spaces in apartment buildings to intrude
into the privacy of apartment interiors. In Whitaker, police of-
ficers brought a drug-sniffing dog into an apartment hallway
and had the dog sniff a particular apartment door. We held
that the dog-sniff at the entrance was a search of the apart-
ment itself and subject to the Fourth Amendment warrant re-
quirement, just as the use of other sense-enhancing technol-
ogy would be. Whitaker, — F.3d at —, 2016 WL 1426484, at *3
(comparing dog-sniff to use of heat-sensing device, binocu-
lars, or stethoscope to look into or listen to interior). Officer
Gasser’s search of the basement crawl space in this case posed
no similar danger of intrusion into the protected privacy of an
apartment interior. Accordingly, the district court correctly
denied the motion to suppress the firearm.
II. Sentencing Issues
   Judge Adelman found that Sweeney was an armed career
criminal, which required a mandatory minimum sentence of
twenty-two years (fifteen years on the firearm possession
charge, and a consecutive seven years for brandishing during
a crime of violence). The judge sentenced Sweeney to the
mandatory minimum twenty-two years in prison, followed
No. 14-3785                                                     15

by three years of supervised release with standard conditions
and several special conditions.
   A. Supervised Release Issues
    In imposing the terms of supervised release, the district
court followed practices long used by district judges in this
circuit and around the country. The judge said he was impos-
ing the “standard conditions” of supervised release without
reciting each of them, without obtaining a waiver of such rec-
itation, and without specifically explaining his reasons for im-
posing each of them. The judge imposed several special con-
ditions of supervised release, including substance abuse treat-
ment, mental health treatment, and payment of restitution,
and provided terse but obviously sound reasons for them.
This was a violent crime committed by a man with a history
of armed violence, substance abuse, and mental health prob-
lems, and who would not be able to pay restitution immedi-
ately. The judge did not explain his reasons for prohibiting
Sweeney from possessing a firearm or dangerous weapon as
a condition of supervised release, but there was no need to
belabor the obvious.
    In a recent series of decisions, however, this court has been
subjecting the imposition of supervised release conditions to
much closer scrutiny than had been common, and we have
done so even when no objections have been raised in district
courts. In particular, see United States v. Siegel, 753 F.3d 705
(7th Cir. 2014); United States v. Thompson, 777 F.3d 368 (7th Cir.
2015); United States v. Sewell, 780 F.3d 839 (7th Cir. 2015);
United States v. Kappes, 782 F.3d 828 (7th Cir. 2015); but cf.
United States v. Silvious, 512 F.3d 364, 371 (7th Cir. 2008) (find-
ing no plain error where district court imposed special condi-
16                                                  No. 14-3785

tions of supervised release that were overly broad). The dis-
trict court neither stated all the conditions orally nor obtained
a waiver for doing so, and did not provide any explanation
for many of the conditions. In addition, some of the specific
conditions imposed here have been found too vague or other-
wise improper, though our circuit law is evolving with re-
spect to some of those conditions, such as the requirement
that the defendant answer truthfully all inquiries by the pro-
bation officer and permit the probation officer to visit his
home at any time. See, e.g., United States v. Douglas, 806 F.3d
979, 985–86 (7th Cir. 2015); United States v. Armour, 804 F.3d
859 (7th Cir. 2015) (condition that probation officer could visit
anytime between 6 a.m. and 11 p.m.). Based on the logic of
our recent cases, we must remand the case. We remand for a
complete re-sentencing in light of the substantial questions
raised in this appeal about Sweeney’s status as an armed ca-
reer criminal, as we explain next.
     B. Armed Career Criminal Status
    The Armed Career Criminal Act provides that a person
convicted of being a felon in possession of a firearm under 18
U.S.C. § 922(g) must receive a mandatory minimum sentence
of fifteen years in prison if he is an armed career criminal. 18
U.S.C. § 924(e)(1). To qualify as an armed career criminal, the
defendant must have had at least three prior convictions for
either certain violent felonies or serious drug offenses. Id.
    The district court found that Sweeney qualified for armed
career criminal status on the basis of four violent felony con-
victions in his record: (1) a 1994 juvenile armed robbery, (2) a
1996 robbery, (3) a 1996 witness intimidation conviction, and
(4) a 2005 burglary. The judge sentenced Sweeney to the fif-
teen-year mandatory minimum as an armed career criminal,
No. 14-3785                                                    17

plus the mandatory consecutive seven years for brandishing
a firearm during a crime of violence. There is no doubt that
Sweeney’s 1996 robbery conviction and 2005 burglary convic-
tion were violent felonies. The legal question is whether either
the 1994 juvenile armed robbery or 1996 witness intimidation
qualifies as a third violent felony.
    Sweeney did not raise objections to his armed career crim-
inal eligibility during sentencing, so we would review the sen-
tence only for plain error. United States v. Thornton, 463 F.3d
693, 700 (7th Cir. 2006). Sweeney has raised substantial ques-
tions about whether courts should use the categorical method
or some other method to determine whether juvenile offenses
qualify as violent felonies under 18 U.S.C. § 924(e)(2)(B) (de-
fining “violent felony” as including an “act of juvenile delin-
quency involving the use or carrying of a firearm, knife, or
destructive device”). Some circuits have applied the categori-
cal approach to juvenile acts. See, e.g., United States v. Wells,
473 F.3d 640, 646–50 (6th Cir. 2007); United States v. Richardson,
313 F.3d 121, 126–28 (3d Cir. 2002).
    Both the Wells and Richardson courts explained that there
are strong arguments both for and against applying the cate-
gorical approach to the firearm, knife, and destructive device
element for juvenile cases. We have not yet decided this legal
question, and a more complete airing of the facts and law con-
cerning Sweeney’s juvenile robbery conviction may shed
more light on his case. Cf. United States v. White, 683 F. Supp.
2d 617, 620–25 (M.D. Tenn. 2010) (where use of firearm in
predicate juvenile delinquency adjudication was disputed in
district court, government offered Shepard materials showing
defendant had been adjudicated guilty of using firearm in vi-
olent felony). Similarly, further development of the record on
18                                                   No. 14-3785

Sweeney’s conviction for intimidation of a witness may clarify
whether it qualifies as a violent felony. Since the case must go
back to the district court in any event and the stakes for the
defendant are so great, we believe the better course is to re-
mand for re-sentencing now rather than leaving the issues for
a likely future petition under 28 U.S.C. § 2255 challenging the
performance of defense counsel.
    The district court may also wish to consider whether these
issues ultimately make a difference to the appropriate sen-
tence here. Even if the categorical approach to the armed ca-
reer criminal issue might bar application of the statutory en-
hancements, the court could consider both of the disputed
convictions and the underlying facts in exercising its judg-
ment under 18 U.S.C. § 3553(a) within the unenhanced statu-
tory ranges. E.g., United States v. Sonnenberg, 628 F.3d 361, 367–
68 (7th Cir. 2010) (categorical approach required vacating of
sentence under Armed Career Criminal Act, but on remand
district court could consider actual facts under § 3553(a)).
   The defendant’s convictions are AFFIRMED, but his sen-
tence is VACATED and the case is REMANDED for re-sen-
tencing consistent with this opinion.
