 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued March 13, 2019                   Decided July 19, 2019

                         No. 15-3015

                UNITED STATES OF AMERICA,
                        APPELLEE

                              v.

                       RODNEY CLASS,
                        APPELLANT


                   On Remand from the
             Supreme Court of the United States


    Leonard R. Powell argued the cause for appellant. With
him on the briefs was Jessica Ring Amunson.

     Lauren R. Bates, Assistant U.S. Attorney, argued the cause
for appellee. With her on the briefs were Jesse K. Liu, U.S.
Attorney, and Elizabeth Trosman, Chrisellen R. Kolb, Jeffrey
Pearlman, and Valinda Jones, Assistant U.S. Attorneys.

   Before: GRIFFITH and SRINIVASAN, Circuit Judges, and
SENTELLE, Senior Circuit Judge.

    Opinion for the Court filed by Circuit Judge GRIFFITH.

    GRIFFITH, Circuit Judge: Federal law prohibits the
possession of firearms on the grounds of the United States
                               2
Capitol. 40 U.S.C. § 5104(e). Rodney Class pleaded guilty to
violating this law after parking a car containing three guns on
a street near the Capitol. He now argues that, as applied to his
case, the law violates the Second Amendment and the Due
Process Clause of the Fifth Amendment. These claims lack
merit, and we affirm his conviction.

                                I

     In May 2013, Rodney Class drove to the United States
Capitol in Washington, D.C. He parked his car in one of the
many angled parking spots that line the 200 block of Maryland
Avenue SW (the “Maryland Avenue lot”). That parking spot
sits just north of the United States Botanic Gardens and
approximately 1,000 feet from the entrance to the Capitol itself.
The street is accessible to the general public, but the parking
spot Class used is reserved on weekdays (like the Thursday he
parked there) for employees of the House of Representatives.
The parking lot is marked by a sign indicating a permit is
required. Class locked his car and walked inside the Capitol.
Upon his return, several police officers were peering into his
car. One asked Class if he had any weapons inside, and he
answered that he did. The officer told Class that it was illegal
to have weapons on Capitol Grounds and took Class to Capitol
Police headquarters. When the car was searched, three firearms
were found.

     Class was indicted for possession of a firearm while on the
grounds of the Capitol, in violation of 40 U.S.C. § 5104(e)(1)
(the “Capitol Grounds ban”). He filed several motions seeking
to dismiss the indictment, arguing, inter alia, that the Capitol
Grounds ban violated his Second Amendment right to bear
arms. The district court denied these motions from the bench,
holding that the Capitol Grounds ban “does not burden conduct
protected by the Second Amendment,” because “laws
                                 3
prohibiting individuals from carrying firearms in sensitive
places, such as government buildings, are presumptively
lawful.” Tr. of Mot. Hr’g at 18, United States v. Class, No.
1:13-cr-0253-1 (D.D.C. Oct. 27, 2014), Dkt. No. 193. Class
subsequently entered an unconditional guilty plea.

     Class appealed his conviction on both constitutional and
statutory grounds. United States v. Class, No. 15-3015, 2016
WL 10950032, at *1 (D.C. Cir. July 5, 2016). We affirmed his
conviction, holding that his unconditional guilty plea waived
his right to appeal on those grounds. Id. at *2. The Supreme
Court reversed, holding that Class did not waive his
constitutional claims because they challenged the
government’s very power to make his conduct criminal. Class
v. United States, 138 S. Ct. 798, 805 (2018).

      On remand, we now consider the merits of those claims:
first, that the ban as applied to Class’s conduct violates his
Second Amendment right to bear arms, and second, that the ban
violates the Fifth Amendment’s Due Process Clause because
the law defining the Capitol Grounds is complicated enough
that Class lacked notice that he was on them. Because these
claims present questions of law, we review them de novo.
United States v. Yakou, 428 F.3d 241, 246 (D.C. Cir. 2005).1
The district court had jurisdiction pursuant to 18 U.S.C. § 3231.
We have appellate jurisdiction pursuant to 28 U.S.C. § 1291.

                                 II


    1
       The government argued during Class’s first appeal that we
should review his due process claim for plain error because he had
not raised it in the district court. See Gov’t. Br. 29-30. On remand,
the government has not revived this argument, and agrees with Class
that our review of his constitutional claims is de novo. See Suppl.
Gov’t. Br. 31.
                               4
     To evaluate the constitutionality of firearms regulations,
we first determine “whether a particular provision impinges
upon a right protected by the Second Amendment.” Heller v.
District of Columbia (Heller II), 670 F.3d 1244, 1252 (D.C.
Cir. 2011). If it does, we ask “whether the provision passes
muster under the appropriate level of constitutional scrutiny.”
Id. Because we conclude that the Capitol Grounds ban does not
“impinge[] upon a right protected by the Second Amendment,”
we do not reach the second question.

     The Second Amendment protects the right to own and
carry a firearm outside the home. Wrenn v. District of
Columbia, 864 F.3d 650, 657-58 (D.C. Cir. 2017); see District
of Columbia v. Heller (Heller I), 554 U.S. 570, 635 (2008). But
the right is not unlimited. The Supreme Court has been careful
to note that “longstanding prohibitions” like “laws forbidding
the carrying of firearms in sensitive places such as schools and
government buildings” remain “presumptively lawful.” Heller
I, 554 U.S. at 626, 627 n.26. A challenger may rebut this
presumption only by “showing the regulation [has] more than
a de minimis effect upon his right” to bear arms. Heller II, 670
F.3d at 1253.

     With respect to the Capitol itself, there are few, if any,
government buildings more “sensitive” than the “national
legislature at the very seat of its operations.” Jeanette Rankin
Brigade v. Chief of the Capitol Police, 421 F.2d 1090, 1093 n.3
(D.C. Cir. 1969). And tragically, gunmen have targeted the
Capitol before. Francis Clines, Capitol Hill Slayings: The
Overview; Gunman Invades Capitol, Killing 2 Guards, N.Y.
TIMES                (July               25,              1998),
https://www.nytimes.com/1998/07/25/us/capitol-hill-slayings-
the-overview-gunman-invades-capitol-killing-2-guards.html.
                               5
     Class, however, was found with a firearm in the Maryland
Avenue parking lot, not the Capitol itself. He argues that Heller
I refers only to bans on possession “in sensitive places like
government buildings,” and the “Maryland Avenue outdoor
parking lot, like most of the Capitol Grounds, is certainly not
‘in a government building.’” Suppl. Class Br. 22. As a result,
he claims, the ban is “outside of any presumption of
constitutionality that applies only ‘in’ sensitive places.” Id.
This argument slices Heller I too thin. The Supreme Court was
careful to note that Heller I’s list of “presumptively lawful”
regulations was not exhaustive, see 554 U.S. at 627 n.26, and
we have little trouble concluding that the same security
interests which permit regulation of firearms “in” government
buildings permit regulation of firearms on the property
surrounding those buildings as well. Indeed, Class appears to
concede this point elsewhere in his brief, agreeing with the
government that the White House lawn, for instance, is
“sensitive” for purposes of the Second Amendment. See Suppl.
Class Br. 25 n.7.

     As for the Maryland Avenue parking lot, although it is not
a government building, we conclude that it is sufficiently
integrated with the Capitol for Heller I’s sensitive places
exception to apply. Accordingly, we conclude that the Second
Amendment does not give Class the right to bear arms in the
Maryland Avenue lot. Several facts lead us to this
determination.

     First, though it is open to the public, the Maryland Avenue
parking lot may be used during working hours only by Capitol
employees with a permit. This makes the area a potential
stalking ground for anyone wishing to attack congressional
staff and disrupt the operations of Congress. The operation of
the national legislature depends not only on the ability of
members of Congress and their staff to conduct business inside
                                6
the Capitol, but also on their ability to freely and safely travel
to and from work. The same special security concerns that
apply to the employees while in the Capitol apply when they
walk to and from their cars on Capitol property.

     Second, the lot is close to the Capitol and legislative office
buildings. Class possessed a firearm less than 1,000 feet away
from the entrance to the Capitol, and a block away from the
Rayburn House Office Building. Although there is surely some
outer bound on the distance Congress could extend the area of
protection around the Capitol without raising Second
Amendment concerns, Congress has not exceeded it here.

     Finally, as the owner of the Maryland Avenue lot, the
government—like private property owners—has the power to
regulate conduct on its property. See Adderly v. Florida, 385
U.S. 39, 47 (1966) (observing in the free-speech context that
the government, “no less than a private owner of property, has
power to preserve the property under its control for the use to
which it is lawfully dedicated”); cf. Bonidy v. U.S. Postal Serv.,
790 F.3d 1121, 1126 (10th Cir. 2015) (observing that when the
U.S. Postal Service acts “as a proprietor rather than as a
sovereign, [it] has broad discretion to govern its business
operations according to the rules it deems appropriate”).

    In sum, because the Maryland Avenue lot has been set
aside for the use of government employees, is in close
proximity to the Capitol building, and is on land owned by the
government, we consider the lot as a single unit with the
Capitol building, and conclude that the lot is a “sensitive” place
where firearms prohibitions are presumptively lawful. Accord
id. at 1125-28 (finding that a post office parking lot is
“sensitive” for Second Amendment purposes); United States v.
Dorosan, 350 F. App’x 874, 875 (5th Cir. 2009) (same).
                               7
     Class raises two counterarguments. First, he tries to
distinguish the Maryland Avenue lot from other outdoor
government property that is protected by security or not
accessible to the public. In support, he points to language from
Wrenn, where we concluded that the Second Amendment
“enables self-defense at least against the level of threat
generally faced by those covered by the Amendment:
responsible and law-abiding citizens.” 864 F.3d at 664. Class
argues that the need to have a gun for self-defense is lessened
in places that are off-limits to the public (like the White House
lawn) or protected by metal detectors and security guards (like
the Capitol building). Because neither is true of the Maryland
Avenue parking lot, Class contends that law-abiding citizens
need to be able to carry firearms for self-defense. Suppl. Class
Reply 4.

     Class reads too much into Wrenn. That case raised the
question of whether the right to bear arms extended outside the
home and who could exercise that right; this case raises the
question of where outside the home a person authorized to
carry a firearm may do so. For this inquiry, we do not look to
the “level of threat” posed in a sensitive place. Many “schools”
and “government buildings”—the paradigmatic “sensitive
places” identified in Heller I—are open to the public, without
any form of special security or screening. In an unsecured
government building like a post office or school, the risk of
crime may be no different than in any other publicly accessible
building, yet the Heller I opinion leaves intact bans on firearm
possession in those places. As one court put it, those places are
“sensitive” for purposes of the Second Amendment because of
“the people found there” or the “activities that take place
there.” GeorgiaCarry.Org, Inc. v. Georgia, 764 F. Supp. 2d
1306, 1319 (M.D. Ga. 2011), aff’d, 687 F.3d 1244 (11th Cir.
2012).
                                8
     Next, Class contends that because the Capitol Grounds ban
was only extended to the Maryland Avenue parking lot in 1980,
with respect to that lot, the ban is not the sort of “longstanding”
regulation that is “presumptively lawful” under Heller I. See
Suppl. Class Br. 25-26. It is true, as we explained in Heller II,
that “[a] requirement of newer vintage is not . . . presumed to
be valid.” 670 F.3d at 1253. Class’s argument, however,
misinterprets what it means for a regulation to be
“longstanding.” Under Class’s reading, the ban in that location
must have been longstanding. But this makes little sense when
viewed through the language of Heller I, which spoke generally
of “schools” and “government buildings.” 554 U.S. at 626-27.
The relevant inquiry is whether a particular type of regulation
has been a “longstanding” exception to the right to bear arms.
See Heller II, 670 F.3d at 1253-56. A new post office is no less
a government building than one built in 1789, just as a new
wing of the Capitol is still part of that building.

    Because the Maryland Avenue parking lot is a sensitive
place, the ban on carrying firearms there is “presumptively
lawful.” Heller I, 554 U.S. at 627 n.26. To rebut that
presumption, Class must show that the ban has “more than a de
minimis effect upon his right” to bear arms. Heller II, 670 F.3d
at 1253. He cannot. Class contends that the Capitol Grounds
ban prevents him from exercising his right to self-defense
while moving about the District, but we rejected a similar
argument in Wrenn, observing:

    [B]ans on carrying only in small pockets of the outside
    world (e.g., near “sensitive” sites) impose only lightly on
    most people’s right to “bear arms” in public. As Judge
    Posner writes: “[W]hen a state bans guns merely in
    particular places, such as public schools, a person can
    preserve an undiminished right of self-defense by not
    entering those places.”
                                9

864 F.3d at 662 (quoting Moore v. Madigan, 702 F.3d 933, 940
(7th Cir. 2012)) (citation omitted). The Maryland Avenue
parking lot is just the kind of “small pocket of the outside
world” where a ban imposes only “lightly” on the right to carry
a weapon in the District of Columbia. If Class “wanted to carry
a gun in his car but abide by the ban,” he could have done so
but parked elsewhere. See Dorosan, 350 F. App’x. at 876.

     Class argues that the Capitol Grounds, which include
almost 300 acres of the District, are not a small pocket of the
outside world, and claims that the ban on possession makes it
“practically impossible to travel to other areas around the
Capitol with a firearm for self-defense.” Suppl. Class Reply 8.
We see no such problem. While this portion of Maryland
Avenue could be used to travel from one part of the District to
another, nothing about the ban prevents a person who wishes
to carry a firearm for self-defense from taking an alternate route
that avoids the Capitol Grounds.

     Class counters by arguing that the boundaries of the
Capitol Grounds are not publicly posted and are therefore
“indistinguishable from nearby areas where firearms are
permitted.” Suppl. Class Br. 14. As a result, he claims that the
fear of violating the ban by accident impinges on his ability to
carry a firearm for self-defense even in areas of the District that
are not technically covered by the ban. To the extent that he
complains about lack of notice, we address that issue in our
discussion of his due process claim. For purposes of his Second
Amendment claim, the Maryland Avenue lot is
“distinguishable” from other nearby areas because Congress
has set apart the Capitol Grounds from the rest of the district
for the use of the national legislature.
                               10
                               III

    Class next argues that he lacked notice his conduct was
criminal because of how difficult it is to determine the
boundaries of the Capitol Grounds. Couching his challenge in
terms of vagueness, Class suggests that absent such notice, his
conviction violates the Due Process Clause of the Fifth
Amendment. We disagree.

     The government violates the Due Process Clause when it
“tak[es] away someone’s life, liberty, or property under a
criminal law so vague that it fails to give ordinary people fair
notice of the conduct it punishes, or so standardless that it
invites arbitrary enforcement.” Johnson v. United States, 135
S. Ct. 2551, 2556 (2015). Most vagueness challenges involve
assertions of “indeterminacy,” in which the defendant claims
that a criminal statute is so “shapeless” that even a person
aware of the law cannot know what conduct is prohibited. Id.
at 2558, 2560. The text of the Capitol Grounds ban, in contrast,
is quite clear: “An individual . . . may not carry on or have
readily accessible . . . on the Grounds or in any of the Capitol
Buildings a firearm.” 40 U.S.C. § 5104(e). Indeed, Class does
not—and could not—argue that any of these terms are
“indeterminate” or “shapeless.” An ordinary citizen would
readily understand from the text of the statute that he may not
carry a firearm on the Capitol Grounds or inside the Capitol.
Nor does Class argue that the boundaries of the Capitol
Grounds are “shapeless.” The metes and bounds of the Capitol
Grounds are precisely defined: with a map of the city and the
appropriate legal references, it can be determined with
certainty that the 200 block of Maryland Avenue SW is subject
to the ban.

    Confronted with a clear statute, Class takes a different
approach. He argues that, regardless of the precision of the text,
                                11
the structure of the statute and lack of signage identifying the
Maryland Avenue lot as a restricted area makes it “exceedingly
difficult” for an ordinary citizen to actually figure out that the
parking lot is part of the Capitol Grounds. Suppl. Class Br. 33.
So difficult, according to Class, that an armed person in the lot
lacks fair notice that his conduct is prohibited. In support of his
position, Class relies on the circuitous route an individual must
take to determine whether the lot is part of the Capitol Grounds.
First, a person must look to the U.S. Code, which defines the
grounds by reference to a 1946 map on file in the Office of the
Surveyor of the District of Columbia. 40 U.S.C. § 5102. The
map does not contain the Maryland Avenue lot. However, the
statute goes on to say that the boundaries of the Grounds
“includ[e] all additions added by law” after the map was
recorded. Id. So the second step a person must take is to find
Public Law 96-432, which in 1980 expanded the Grounds to
include “that portion of Maryland Avenue Southwest from the
west curb of First Street Southwest to the east curb of Third
Street Southwest.” Act to Amend the Act of July 31, 1946, as
amended, Relating to the United States Capitol Grounds, and
for Other Purposes, Pub. L. No. 96-432, (5), 94 Stat. 1851,
1851 (1980). The Maryland Avenue lot falls squarely within
this area, but Class argues that the combination of these steps
and lack of other identifying features puts determining the
boundaries of the Capitol Grounds “beyond the ken of someone
of ordinary intelligence and diligence.” Suppl. Class Br. 34.

     We disagree. It is a bedrock principle that “[c]itizens are
charged with generally knowing the law.” United States v.
Bronstein, 849 F.3d 1101, 1107 (D.C. Cir. 2017). Fair notice
usually requires a legislature to “do nothing more than enact
and publish the law, and afford the citizenry a reasonable
opportunity to familiarize itself with its terms and to comply.”
Id. (quoting Texaco, Inc. v. Short, 454 U.S. 516, 532 (1982)).
Although determining that the ban applies to the Maryland
                               12
Avenue lot is not completely straightforward, we cannot say
that the law is so difficult to understand that it violates the
Constitution, for “perfect clarity and precise guidance have
never been required even of regulations that restrict [protected]
activity.” Ward v. Rock Against Racism, 491 U.S. 781, 794
(1989).

     The statutory provisions at issue here were enacted and
published decades ago. See Act of Oct. 20, 1967, Pub. L. No.
90-108, 81 Stat. 275, 276 (banning firearms on Capitol
Grounds); Pub. L. No. 96-432 (extending Grounds to include
the Maryland Avenue lot). The laws do not use complicated
phrasing or specialized vocabulary, referring only to the names
of streets that appear on road signs and which can be located
on widely available maps of the District. And though it is true
that the relevant provisions of the U.S. Code do not themselves
reference the Maryland Avenue lot, Class points to no case in
which a court has held that due process turns on whether a law
was codified or merely enacted and published as a Public Law.
Class’s argument has even less force when considered
alongside the version of the U.S. Code published by the
Government Printing Office, which includes as an appendix to
the text of 40 U.S.C. § 5104 a section entitled “Changes in
United States Capitol Grounds.” 40 U.S.C. § 5104 (2012). That
section contains the text of enactments altering the boundaries
of the Grounds, including the 1980 amendment that added the
Maryland Avenue lot. Id.

     The only case that Class identifies in which a court has
struck down a law due to the difficulty of determining
geographic boundaries is Doe v. Snyder, which involved a
statute that prohibited registered sex-offenders from coming
within 1,000 feet of “school property” used for “educational
instruction” or “sports or other recreational activities.” 101 F.
Supp. 3d 672, 682-83 (E.D. Mich. 2015). The district court
                               13
concluded that the law violated due process because it was
unclear how to measure the 1,000 feet (i.e., from the entrance
to the building or from the edge of school property lines) and it
would be “difficult for . . . registrants to parse through school-
owned real property [records]” to determine which parcels
were used for covered activities. Id. at 682-85. We are of course
not bound by the reasoning of that district court, but in any
event, Doe is easily distinguishable. The Capitol Grounds are
defined by a map and a specific list of intersections and streets
that are part of the public law. A citizen concerned about
violating the ban need not make detailed measurements, sort
through voluminous real estate records, or speculate about the
uses of various parcels of land. He must simply, as is the case
with any criminal law, open the statute book—even if here he
may need two.

     This case more closely resembles Klein v. San Diego
County, 463 F.3d 1029, 1039 (9th Cir. 2006), in which the
Ninth Circuit upheld a ban on picketing within 300 feet of a
dwelling. That court conceded that the ordinance might be
unconstitutional “if it were impossible for the picketers to
determine the 300-foot boundary with any precision.” Id. But
maps showing where dwellings were located were available in
the County Tax Assessor’s office, and a “would-be picketer,
with the lot map in hand,” could “estimate the boundary with
some level of precision.” Id. Indeed, the Capitol Grounds ban
asks even less of a would-be visitor to the Capitol, because no
estimation or measurement is required.

     Class nevertheless resists the conclusion that the law
provides sufficient notice. He argues that even if the Capitol
Grounds ban is not impossible to understand, a heightened
level of review is applicable here and requires us to strike down
the law. He suggests this is so because “[t]he degree of
vagueness that the Constitution tolerates—as well as the
                                  14
relative importance of fair notice and fair enforcement—
depends in part on the nature of the enactment.” Village of
Hoffman Estates v. Flipside, Hoffman Estates, Inc., 455 U.S.
489, 498 (1982). Class is correct that our analysis must be more
searching in cases in which a law imposes criminal penalties,
“threatens to inhibit the exercise of constitutionally protected
rights,” and lacks a scienter requirement. Id. at 498-99; see
Suppl. Class Br. 33. Class is also right that all three of those
factors triggering additional skepticism are present here. First,
the Capitol Grounds ban imposes significant criminal
penalties. 40 U.S.C. § 5109. Second, the ban at least implicates
the right to bear arms, even if it does not violate the Second
Amendment. Cf. N.Y. State Rifle & Pistol Ass’n, Inc. v. Cuomo,
804 F.3d 242, 265 (2d Cir. 2015) (applying a “more stringent”
vagueness standard to a gun regulation).

     The third factor “affecting the clarity that the Constitution
demands of a law” is whether a statute possesses a scienter
requirement, an inquiry that, at least in this appeal, needs some
explanation. Hoffman Estates, 455 U.S. at 499. “Scienter” is
“the degree of knowledge sufficient to ‘mak[e] a person legally
responsible for the consequences of his or her act or
omission.’” Rehaif v. United States, 139 S. Ct. 2191, 2195
(2019) (quoting BLACK’S LAW DICTIONARY 1547 (10th ed.
2014)). Here, the district court interpreted the Capitol Grounds
ban as requiring knowledge as to the possession of a firearm,
but not as to presence on the Capitol Grounds. 2 According to
Class, the fact that an armed person who unknowingly wanders
onto the grounds could violate the statute counsels against
concluding that the law provides sufficient notice of the
conduct it proscribes.

     2
       As we discuss in greater detail below, we are not confronted
with the question of whether the district court’s interpretation of the
statute was correct.
                                15

     We agree that the district court’s determination that the
Capitol Grounds ban lacks a scienter requirement means “that
the Constitution tolerates” a lesser “degree of vagueness” than
would be permissible had the court reached the contrary
conclusion. Hoffman Estates, 455 U.S. at 498. Indeed, we have
relied on the presence of a scienter requirement to uphold laws
in the face of vagueness challenges. See, e.g., Wash.
Mobilization Comm. v. Cullinane, 566 F.2d 107, 118 (D.C. Cir.
1977) (holding that a regulation prohibiting the crossing of a
police line comports with the Due Process Clause so long as
“the location of the line is clearly indicated and if adequate
notice is given”); accord United States v. Nieves-Castano, 480
F.3d 597, 603-04 (1st Cir. 2007).

     The question on appeal, however, is not whether the more
searching standard from Hoffman Estates applies. It does. The
question on appeal is whether Class’s conviction violates the
Due Process Clause because of how vague the statute is. It does
not. As we noted above, the steps necessary for determining the
special status of the Maryland Avenue lot are not the most
straightforward. But the statute is sufficiently clear to “give [a]
person of ordinary intelligence a reasonable opportunity to
know what is prohibited.” Hoffman Estates, 455 U.S. at 498
(quoting Grayned v. City of Rockford, 408 U.S. 104, 108-09
(1972)). That is ultimately what the Due Process Clause
requires, and that standard has been met. Cf. Klein, 463 F.3d at
1039 (upholding against a vagueness challenge a picketing ban
despite the lack of a scienter requirement).

     We note in closing that the lack of a scienter requirement
in the ban might raise issues of statutory construction. But
Class has waived those arguments. In two cases, including one
decided very recently, the Supreme Court has concluded that
restrictions on the possession of firearms require proof of
                               16
scienter. Rehaif, 139 S. Ct. at 2200 (“[T]he Government must
prove both that the defendant knew he possessed a firearm
and that he knew he belonged to the relevant category of
persons barred from possessing a firearm.”); Staples v.
United States, 511 U.S. 600, 619 (1994) (“[T]o obtain a
conviction, the Government should have been required to
prove that [the defendant] knew of the features of his [gun] that
brought it within the scope of the [prohibition].”). The parallel
is clear: Rehaif concerned a ban on possession of a gun by a
person with a particular immigration status; Staples concerned
a ban on possession of a particular type of gun; and this case
concerns a ban on possession of a gun in a particular place.

     But those cases resolved only “question[s] of statutory
construction,” not the constitutional right to due process.
Staples, 511 U.S. at 604; see Rehaif, 139 S. Ct. at 2194. That
is, Staples and Rehaif both concluded that Congress had not
intended to impose criminal penalties for possession of a gun
without proof of scienter; neither case addressed whether or not
Congress lacks the power to impose such penalties. And here,
the Supreme Court held only that the claims which survived
Class’s guilty plea were those that “challenge the
Government’s power to criminalize” his conduct. See Class,
138 S. Ct. at 805. We therefore reiterate our prior holding that
Class waived his statutory claims. And to succeed on his
constitutional challenge, it is not enough for Class to show that
the best reading of the law requires proof of scienter. Instead,
Class must show that the law is so difficult for the average
person to understand that the Constitution forbids his
conviction without such proof.

    He cannot meet that heavy burden. As we discuss above,
determining that the ban applies to the Maryland Avenue lot is
not a perfectly straightforward exercise, but citizens are
presumed to know the law, and the task of ascertaining the
                            17
boundaries of the Capitol Grounds is not so difficult that
Class’s conviction violates the Constitution.

                            IV

    For the foregoing reasons, the judgment of the district
court is affirmed.

                                                So ordered.
