                FOR PUBLICATION

  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT


UNITED STATES OF AMERICA,                Nos. 11-30276
                Plaintiff-Appellee,           12-30070

                 v.                         D.C. No.
                                         3:10-cr-00091-
SABIL M. MUJAHID,                            HRH-1
             Defendant-Appellant.
                                            OPINION


      Appeal from the United States District Court
               for the District of Alaska
   H. Russel Holland, Senior District Judge, Presiding

          Argued and Submitted June 2, 2014
         Submission Vacated October 23, 2014
            Resubmitted August 27, 2015
                 Anchorage, Alaska

                 Filed August 27, 2015

  Before: J. Clifford Wallace, Kim McLane Wardlaw,
         and Morgan Christen, Circuit Judges.

               Opinion by Judge Christen
2                 UNITED STATES V. MUJAHID

                           SUMMARY*


                          Criminal Law

   The panel affirmed defendant’s convictions for four
counts of sexual abuse and three counts of abusive sexual
contact while an inmate at the Anchorage Correctional
Complex.

    The panel held that 18 U.S.C. §§ 2241, 2242, and 2244,
which criminalize sexual assaults in facilities where federal
inmates are held by agreement with state and local
governments, are not facially unconstitutional; they are a
necessary and proper means of exercising the federal
authority that permits Congress to create federal criminal
laws, to punish their violations, to imprison violators, to
provide appropriately for those imprisoned, and to maintain
the security of those who are not imprisoned but who may be
affected by the federal imprisonment of others.

    The panel held, for the same reasons, that §§ 2241, 2242,
and 2244 are plainly constitutional as applied to an individual
in federal custody who is being held in a state facility
pursuant to a contract with a federal agency.

   The panel held that in prosecutions under §§ 2241, 2242,
and 2244, the district court may determine as a matter of law
whether the facility at which the alleged crime took place is
one “in which persons are held in custody by direction of or


  *
    This summary constitutes no part of the opinion of the court. It has
been prepared by court staff for the convenience of the reader.
                UNITED STATES V. MUJAHID                     3

pursuant to a contract or agreement with the head of any
Federal department or agency.”


                         COUNSEL

John P. Balazs (argued), Law Office of John P. Balazs,
Sacramento, California, for Defendant-Appellant.

Jo Ann Farrington (argued), Assistant United States Attorney;
Karen Loeffler, United States Attorney, United States
Attorney’s Office, Anchorage, Alaska, for Plaintiff-Appellee.


                         OPINION

CHRISTEN, Circuit Judge:

     Sexual assault by and against prison inmates is a
distressing and pernicious problem. In this case, we decide
whether the Constitution gives Congress the power to address
it by criminalizing sexual assaults in facilities where federal
inmates are held by agreement with state and local
governments. We also decide whether the existence of such
an agreement is a question of law that may be decided by the
trial court. Our answer to both questions is “yes.”

                     BACKGROUND

    On March 5, 2009, Sabil Mumin Mujahid was arrested in
Anchorage, Alaska after officers found a firearm in the trunk
of a car he had driven to the Nesbett Courthouse for a bail
hearing on a pending state drug charge. Mujahid was taken
to the Anchorage Correctional Complex, which provides
4                      UNITED STATES V. MUJAHID

housing for state prisoners as well as federal prisoners
pursuant to a contract with the U.S. Marshals Service.

    The day after his arrest, Mujahid was charged in a federal
criminal complaint with one count of being a felon in
possession of a firearm.1 The federal court ordered him
detained pending trial, and thereafter the state court revoked
his bail on the drug charge. In June 2009, a jury convicted
Mujahid on the federal felon-in-possession charge. The
federal court sentenced Mujahid to 120 months’
imprisonment.2 On June 28, 2010—after the state drug
charge was resolved—Mujahid was transferred from the
Anchorage Correctional Complex to a federal prison in
Washington state.

    During his time at the Anchorage Correctional Complex,
Mujahid repeatedly sexually assaulted other prisoners. As a
result, he was charged with multiple counts of aggravated
sexual abuse, sexual abuse, and abusive sexual contact, in
violation of 18 U.S.C. §§ 2241, 2242, and 2244, respectively.

    18 U.S.C. § 2241 defines and proscribes aggravated
sexual abuse by any person “in the special maritime and
territorial jurisdiction of the United States or in a Federal
prison, or in any prison, institution, or facility in which
persons are held in custody by direction of or pursuant to a
contract or agreement with the head of any Federal
department or agency.” (Emphasis added.) 18 U.S.C.
§§ 2242 and 2244 define and proscribe sexual abuse and


    1
        A grand jury indicted him on this charge twelve days later.
 2
   We later affirmed the judgment of conviction and the sentence. See
United States v. Mujahid, 433 F. App’x 559 (9th Cir. 2011).
                UNITED STATES V. MUJAHID                      5

abusive sexual contact, respectively, under the same
circumstances.

     Before trial, Mujahid moved to dismiss the indictment on
the ground that the “the Constitution does not confer upon the
National Government the power to suppress violent crime
that occurs in state jails.” He argued that 18 U.S.C. §§ 2241,
2242, and 2244 exceed Congress’ authority under Article I of
the Constitution and contravene the Tenth Amendment, both
“facially and as applied.” Mujahid did not explain, however,
why the statutes would be unconstitutional as applied to him
if they are constitutional on their face.

    The district court denied Mujahid’s motion to dismiss. In
April 2011, the government filed a second superseding
indictment, which added additional counts under the same
statutes. The parties stipulated that the district court’s order
on the motion to dismiss applied to all counts in the second
superseding indictment.

    Mujahid was tried before a jury in June 2011. At trial,
Deputy U.S. Marshal Rochelle Liedike testified on behalf of
the government concerning the Anchorage Correctional
Complex. Liedike explained that there are no federal prisons
in Alaska, but that the U.S. Marshals Service has a contract
with the Alaska Department of Corrections to house federal
prisoners. Liedike testified that the majority of federal
inmates in Alaska are detained at the Anchorage Correctional
Complex, where the Marshals Service has contracted for 60
beds. She authenticated a copy of the contract, which was
introduced into evidence as Exhibit 23. Liedike confirmed
that the contract was in effect from May 3, 2009, through
May 26, 2010—the period during which the events charged
in the second superseding indictment took place.
6                   UNITED STATES V. MUJAHID

     At the end of the trial, the district court told counsel that
it would use the Ninth Circuit Pattern Jury Instructions to
instruct the jury that the government must prove beyond a
reasonable doubt that “the offense was committed at the
Anchorage Correctional Complex.”3 Mujahid objected,
arguing that the jury should also have to determine whether
the Anchorage Correctional Complex is “a facility in which
persons are held in custody by direction of or pursuant to a
contract or agreement with the head of any Federal
department or agency.” See 18 U.S.C. §§ 2241, 2242, 2244.
The district court overruled this objection, stating “the
existence of the contract is a legal question for the Court to
decide, and the fact question that’s for the jury to decide is
simply was the victim housed in, you know, the institution.”
The court subsequently granted the government’s unopposed
motion for a legal finding on the record, and “conclude[d]
that, as a matter of law, the Anchorage Correctional Complex
is a facility in which persons are held in custody pursuant to
an agreement with the United States Marshals Service, a
federal agency.”

   Mujahid was convicted of four counts of aggravated
sexual abuse in violation of 18 U.S.C. § 2241 and three
counts of abusive sexual contact in violation of 18 U.S.C.


    3
    The pattern jury instructions for 18 U.S.C. §§ 2241, 2242, and 2244
state that the jury must find “the offense was committed at [specify place
of federal jurisdiction].” See Ninth Circuit Pattern Criminal Jury
Instructions §§ 8.164, 8.170, 8.179. The comments to Instruction 8.164
explain: “Whether the crime alleged occurred at a particular location is a
question of fact. Whether the location is within the special maritime and
territorial jurisdiction of the United States or a federal prison is a question
of law.” The comments do not address the provision concerning facilities
where federal detainees are held pursuant to a contract, which was added
to the statute relatively recently.
                UNITED STATES V. MUJAHID                      7

§ 2244. The district court sentenced him to 480 months’
imprisonment. Mujahid timely filed a notice of appeal from
the judgment in September 2011.

    Four months later, Mujahid filed a pro se motion for a
new trial in district court. Mujahid argued that the
government withheld evidence, namely, a memorandum letter
and remand detainer that “could have showed that comity was
with the State of Alaska at the time of the allege[d] assault on
John Doe 3 and John Doe 6.” Mujahid contended that after
he was convicted on the federal felon-in-possession charge,
the federal government transferred “custody back to the State
of Alaska” so Mujahid could be tried on the state drug
charges. The district court correctly determined that while it
did not have jurisdiction to grant the motion absent a remand
from this court, it did have jurisdiction to deny the motion.
See United States v. Hays, 454 F.2d 274, 275 (9th Cir. 1972)
(per curiam). The court ruled it would decline to seek a
remand “when defendant is currently represented by
counsel.” Mujahid filed a second notice of appeal from the
order denying his pro se motion for a new trial. We sua
sponte consolidated Mujahid’s two appeals.

   JURISDICTION AND STANDARD OF REVIEW

   We have jurisdiction under 28 U.S.C. § 1291. We review
de novo whether a criminal statute is an unconstitutional
overreach of congressional authority. United States v. Bohn,
622 F.3d 1129, 1133 (9th Cir. 2010). We also review de
novo whether the district court’s jury instructions omitted an
element of the charged offense. United States v. Cherer,
513 F.3d 1150, 1154 (9th Cir. 2008).
8                  UNITED STATES V. MUJAHID

                           DISCUSSION

    Mujahid raises two arguments in this appeal. First, he
argues the district court erred by denying his motion to
dismiss the indictment because the statutes of conviction are
unconstitutional. Second, he argues that whether the
Anchorage Correctional Complex is a facility in which
persons are held pursuant to a contract with the head of a
federal agency is a question of fact that should have been
determined by the jury, not the trial judge. We address each
issue in turn.

I. The district court correctly denied Mujahid’s motion
   to dismiss the indictment.

        A. The challenged          statutes      are     not     facially
           unconstitutional.

    As originally enacted in 1986, the statutes of conviction
proscribed aggravated sexual abuse, sexual abuse, and
abusive sexual contact by any person “in the maritime and
territorial jurisdiction of the United States or in a Federal
prison.”4 Sexual Abuse Act of 1986, Pub. L. No. 99-654, 100
Stat. 3660 (codified as amended at 18 U.S.C. §§ 2241–2244).
In 2003, Congress passed the Prison Rape Elimination Act,
which contained measures designed to reduce the widespread
incidence of sexual assault in prisons, such as grants to states


    4
    Prior to 1986, federal law criminalized rape occurring in the special
territorial jurisdiction of the United States. The Sexual Abuse Act of 1986
was designed to ensure the federal government had jurisdiction over sex
offenses occurring in prisons not located within the United States’ special
territorial jurisdiction. See H.R. Rep. No. 99-594, at 12 (1986), reprinted
in 1986 U.S.C.C.A.N. 6186, 6192.
                UNITED STATES V. MUJAHID                      9

for prevention of prison rape and the establishment of a
National Prison Rape Reduction Commission. Prison Rape
Elimination Act of 2003, Pub. L. No. 108-79, 117 Stat. 972.
Then, in 2006, Congress expanded the jurisdictional reach of
the statutes of conviction to include offenses “in any prison,
institution, or facility in which persons are held in custody by
direction of or pursuant to a contract or agreement with the
Attorney General.”           Violence Against Women and
Department of Justice Reauthorization Act of 2005, Pub. L.
No. 109-162, § 1177(a), 119 Stat. 2960, 3125 (2006)
(codified as amended at 18 U.S.C. §§ 2241–2244).

    This 2006 amendment is the focus of Mujahid’s
constitutional claim. Mujahid argues the “police power”
belongs to the states, and Congress acted beyond its limited,
enumerated powers when it extended the statutory reach to
cover sexual abuse that occurs in state and local institutions
where federal detainees are held pursuant to a contract with
a federal agency. The government responds that the 2006
amendment was a proper exercise of Congress’ authority to
pass “necessary and proper” laws concerning federal
prisoners.

    In evaluating Mujahid’s claim, we are mindful that
Mujahid bears a “heavy burden” to demonstrate the statutes
are not within the scope of Congress’ constitutional authority.
See United States v. Salerno, 481 U.S. 739, 745 (1987). The
Supreme Court has explained that “[a] facial challenge to a
legislative Act is . . . the most difficult challenge to mount
successfully, since the challenger must establish that no set of
circumstances exists under which the Act would be valid.”
Id.; see also Hotel & Motel Ass’n of Oakland v. City of
Oakland, 344 F.3d 959, 971 (9th Cir. 2003) (explaining
Salerno is the standard for demonstrating a statute is facially
10                  UNITED STATES V. MUJAHID

unconstitutional       “outside       the    context      of the First
Amendment”).

    “[T]he Necessary and Proper Clause grants Congress
broad authority to enact federal legislation.” United States v.
Comstock, 560 U.S. 126, 133 (2010). In general, a statute is
within the scope of Congress’ authority as long as it
“constitutes a means that is rationally related to the
implementation of a constitutionally enumerated power.” Id.
at 134; see also United States v. Kebodeaux, 133 S. Ct. 2496,
2503 (2013). Thus, although “‘Congress cannot punish
felonies generally,’” Bond v. United States, 134 S. Ct. 2077,
2086 (2014) (quoting Cohens v. Virginia, 6 Wheat. 264, 428
(1821)), it is well established that Congress may create
federal crimes under the Necessary and Proper Clause, see
Comstock, 560 U.S. at 135–36. Indeed, Mujahid forthrightly
acknowledges that “Congress routinely exercises its authority
to enact criminal laws in furtherance of, for example, its
enumerated powers to regulate interstate and foreign
commerce, to enforce civil rights, . . . and so forth.” See id.
at 136. Mujahid also acknowledges that as a corollary to its
power to enact federal criminal laws, Congress may establish
a prison system and “enact laws that seek to ensure that
system’s safe and responsible administration [as well as] the
safety of the prisoners, prison workers and visitors, and those
in surrounding communities.”5 Id. at 137.

  5
    As an example of a law designed to ensure prison safety, Comstock
cited 18 U.S.C. § 1791, a statute that prohibits smuggling of contraband.
See Comstock, 560 U.S. at 137. That statute contains a jurisdictional
provision virtually identical to the jurisdictional provision in the statutes
here. See 18 U.S.C. § 1791(d)(4) (defining “prison” to include “any
prison, institution, or facility in which persons are held in custody by
direction of or pursuant to a contract or agreement with the Attorney
General”).
                   UNITED STATES V. MUJAHID                            11

    In Comstock, applying these principles, the Supreme
Court upheld a federal civil-commitment statute authorizing
the continued detention of “a mentally ill, sexually dangerous
federal prisoner beyond the date the prisoner would otherwise
be released.” Id. at 129 (citing 18 U.S.C. § 4248). The Court
concluded the statute was “a ‘necessary and proper’ means of
exercising the federal authority that permits Congress to
create federal criminal laws, to punish their violation, to
imprison violators, to provide appropriately for those
imprisoned, and to maintain the security of those who are not
imprisoned but who may be affected by the federal
imprisonment of others.” Id. at 149. In reaching this
conclusion, the Court considered five factors: “(1) the breadth
of the Necessary and Proper Clause, (2) the long history of
federal involvement in this arena, (3) the sound reasons for
the statute’s enactment in light of the Government’s custodial
interest . . . , (4) the statute’s accommodation of state
interests, and (5) the statute’s narrow scope.” Id. Mujahid
argues these factors cut in the direction of unconstitutionality
in this case. We disagree.

    First, as we have explained, the Necessary and Proper
Clause grants Congress broad power to enact legislation,
including legislation designed to facilitate appropriate
enforcement of federal criminal laws enacted in furtherance
of Congress’ enumerated powers. See id. at 133–37.

   Second, Congress has long been involved in legislating
the terms of federal imprisonment.6      See Ex parte


 6
   Until the 1900s, there were no federal prisons, so all federal prisoners
were housed in state facilities. See Howe v. Smith, 452 U.S. 473, 483
(1981). In the 1800s, Congress gave the federal courts and later the
Attorney General broad authority to assign federal prisoners to a suitable
12                UNITED STATES V. MUJAHID

Karstendick, 93 U.S. 396, 398–401 (1876). Mujahid urges us
to focus specifically on the federal government’s involvement
in proscribing sexual abuse at state or local prisons. But in
Comstock, the Court looked not to the history of the particular
statute at issue in that case, but rather to the broader history
of federal involvement “in the delivery of mental health care
to federal prisoners,” including through civil commitment.
560 U.S. at 137–38. Here, the federal government has been
directly involved in the safe and orderly incarceration of
federal prisoners since at least 1891, when the federal prison
system was established. Congress enacted 18 U.S.C.
§§ 2241, 2242, and 2244 to aid “the Federal Government’s
obligation to maintain order within prisons.” See H.R. Rep.
No. 99-594, at 12 (1986), reprinted in 1986 U.S.C.C.A.N.
6186, 6192. The 2006 amendment extending jurisdiction
over offenses that take place in state facilities where federal
prisoners are housed strikes us as a “modest addition to a
longstanding federal statutory framework.” See Comstock,
560 U.S. at 142.

    Third, the statutes here, like the civil commitment statute
in Comstock, are “‘reasonably adapted’ to Congress’ power
to act as a responsible federal custodian.” Id. at 143 (quoting
United States v. Darby, 312 U.S. 100, 121 (1941)). Congress
has found a “high incidence of sexual assault within prisons,”
which has numerous detrimental effects on both inmates and
the broader community. See 42 U.S.C. § 15601. Congress
has a strong interest in and obligation to create a safe
environment for federal prisoners and those housed with
federal prisoners, including by preventing sexual assaults. To


prison. See Cosgrove v. Smith, 697 F.2d 1125, 1135–36 (D.C. Cir. 1983).
Federal law provided that federal prisoners would be subject to the same
conditions as state prisoners. See id. at 1136.
                UNITED STATES V. MUJAHID                     13

do anything less would risk denying prisoners their Eighth
Amendment rights. See id. (explaining sexual assault within
prisons “involves actual and potential violations of the United
States Constitution”); Farmer v. Brennan, 511 U.S. 825,
832–34 (1994) (prison official’s deliberate indifference to
substantial risk of serious harm violates prisoners’ right to be
free from cruel and unusual punishment). Mujahid argues the
statutes are unnecessary because all fifty states criminalize
sex offenses. But even if this is true, there is no guarantee a
state will choose to prosecute an offense committed by or
against a federal prisoner that occurs in a state prison, and at
any rate, Congress’ power is not dependent on state inaction.
See Comstock, 560 U.S. at 134 (Congress may enact laws
“rationally related to the implementation of a constitutionally
enumerated power”).

    Fourth, although the statutes at issue do not expressly
accommodate state interests, the government correctly
observes that they “do not supplant State legislation
addressing the same topic; rather, like many federal criminal
statutes, they create concurrent and complementary
jurisdiction.”

    Finally, the links between the statutes and an enumerated
Article I power “are not too attenuated.” See id. at 146. As
we have explained, Congress may enact criminal laws to
implement its enumerated powers, as well as other laws to
ensure the just punishment of those convicted under federal
criminal laws. Mujahid points out that the statutes “cover
offenses committed by state inmates, state employees, and
persons who visit inmates in state custody at any institution
where federal inmates are held” pursuant to a contract with a
federal agency. But this case involves a crime committed by
a federal inmate, not a crime committed by one state inmate
14                  UNITED STATES V. MUJAHID

against another. Even assuming Congress could not authorize
federal jurisdiction over the latter scenario,7 the statutes are
not so overbroad as to completely exceed Congress’ power
under the Necessary and Proper Clause. See Salerno,
481 U.S. at 745.

    Like the civil commitment statute in Comstock, 18 U.S.C.
§§ 2241, 2242, and 2244 are not facially unconstitutional;
they are “a ‘necessary and proper’ means of exercising the
federal authority that permits Congress to create federal
criminal laws, to punish their violation, to imprison violators,
to provide appropriately for those imprisoned, and to
maintain the security of those who are not imprisoned but
who may be affected by the federal imprisonment of others.”8
See Comstock, 560 U.S. at 149.

      B. Mujahid has not shown the statutes are
         unconstitutional as applied to him.

    In his opening brief on appeal, Mujahid argues the
statutes of conviction may be unconstitutional as applied to
him because “the State of Alaska may have had primary
custody and jurisdiction over him since his initial arrest.” He
seeks remand to the district court for this determination. In
response, the government correctly points out that although
Mujahid’s motion to dismiss the indictment nominally
challenged the constitutionality of the statutes “facially and
as applied,” it did not indicate that Mujahid might be in state


 7
     We emphasize that we do not decide this question.
 8
   Because we decide the statutes are constitutional under the Necessary
and Proper Clause, we need not consider the government’s alternative
Spending Clause argument.
                   UNITED STATES V. MUJAHID                             15

custody or otherwise articulate any facts that would support
an as-applied challenge to the statutes. Mujahid replies that
the “as-applied” challenge raised in the motion to dismiss is
based on his status as “a federal pre-trial detainee being held
with mostly state inmates at the Anchorage Correctional
Complex pursuant to a contract with the U.S. Marshals
Service.” He contends this is a “separate and distinct”
argument from his post-trial, pro se claim that the state had
primary custody over him.

    Mujahid thus effectively concedes that the motion to
dismiss the indictment did not articulate an as-applied
challenge; it was premised on the assumption that Mujahid
was a federal detainee.9 For the reasons set forth in the
previous section, 18 U.S.C. §§ 2241, 2242, and 2244 are
plainly constitutional as applied to an individual in federal
custody who is being held in a state facility pursuant to a
contract with a federal agency.

    Until he filed his pro se motion for a new trial, Mujahid
did not raise the argument that he may have been in state
custody when the assaults took place. Because Mujahid was
represented by counsel, the district court acted within its
discretion by declining to seek a remand in order to consider
this argument. See United States v. Bergman, 813 F.2d 1027,
1030 (9th Cir. 1987) (“A criminal defendant does not have an
absolute right to both self-representation and the assistance of
counsel. The decision to allow such hybrid representation is
within the sound discretion of the [trial] judge.” (citation
omitted)). The district court did not rule on Mujahid’s as-
applied challenge. We also decline to do so. See Davis v.

   9
     There is no dispute that the assaults took place after Mujahid was
federally indicted and ordered detained pending trial on the federal charge.
16                UNITED STATES V. MUJAHID

Nordstrom, Inc., 755 F.3d 1089, 1094 (9th Cir. 2014)
(explaining federal appellate court will “not consider an issue
not passed upon below” when record has not been fully
developed (internal quotation marks omitted)).10

II. The district court properly decided the jurisdictional
    component of the statutes of conviction as a matter of
    law.

    Mujahid argues the district court erred by deciding as a
matter of law that the Anchorage Correctional Complex is a
“facility in which persons are held in custody . . . pursuant to
a contract or agreement with the head of any Federal
department or agency,” see 18 U.S.C. §§ 2241, 2242, 2244,
and instructing the jury that it need only determine whether
the crimes in fact occurred at the Anchorage Correctional
Complex. Mujahid relies primarily on United States v.
Gaudin, 515 U.S. 506 (1995).

    In Gaudin, the defendant was convicted of making
material false statements in a matter within the jurisdiction of
a federal agency, in violation of 18 U.S.C. § 1001. Id. at 507.
The district court concluded, based on testimony proffered by
the government, that the alleged false statements were
material, and it so instructed the jury. Id. at 508. The
Supreme Court concluded the district court violated the
defendant’s Fifth and Sixth Amendment right to have the jury
determine each element of the crime beyond a reasonable
doubt. Id. at 522–23. The Court rejected the government’s
argument that the Constitution requires the jury to determine
only the facts underlying the materiality determination. Id. at

   10
      The district court remains free to reconsider this issue upon an
appropriate motion.
                UNITED STATES V. MUJAHID                    17

514 (“[T]he jury’s constitutional responsibility is not merely
to determine the facts, but to apply the law to those facts and
draw the ultimate conclusion of guilt or innocence.”).

     After Gaudin, we have approved of the trial court
deciding the jurisdictional component of a crime to the extent
it presents a pure question of law with no disputed questions
of fact underlying it. See, e.g., United States v. Smith,
282 F.3d 758, 767 (9th Cir. 2002) (“A district court may
determine as a matter of law the existence of federal
jurisdiction over [a] geographic area, but the locus of the
offense within that area is an issue for the trier of fact.”
(quoting United States v. Warren, 984 F.2d 325, 327 (9th Cir.
1993)) (internal quotation marks omitted)). Thus, for
example, in United States v. Perlaza, we held that the
Maritime Drug Law Enforcement Act was unconstitutional
insofar as it required the district court to determine a
jurisdictional component—whether a vessel was stateless—
that turned on disputed questions of fact. 439 F.3d 1149,
1165–67 (9th Cir. 2006). By contrast, in United States v.
Zakharov, we held the district court could decide the
jurisdictional component—whether a vessel was subject to
the United States’ jurisdiction where the flag nation had given
its consent—because the issue did not turn on disputed
questions of fact. 468 F.3d 1171, 1176 & n.3 (9th Cir. 2006).

    Similarly, we have held that the “existence of [a] contract
based on undisputed facts is a question of law.” Chateau des
Charmes Wines Ltd. v. Sabate USA Inc., 328 F.3d 528, 530
(9th Cir. 2003) (per curiam) (citing Helash v. Ballard,
638 F.2d 74, 75 (9th Cir. 1980) (per curiam)). Here, there is
no factual dispute concerning the existence of a contract
between the U.S. Marshals Service and the Alaska
Department of Corrections to house federal prisoners at the
18                 UNITED STATES V. MUJAHID

Anchorage Correctional Complex. Mujahid’s opening brief
does not point to any facts that would undermine the validity
of the specific written contract introduced by the government
at trial.11 We conclude, therefore, that the existence of this
contract is a question of law, as there is no factual question
for the jury to decide. Cf. id. (“[W]hether the parties agreed
to a forum selection clause is a question of law[.]”).

    Mujahid argues that it was error for the district court not
to let the jury make this determination because it involves a
mixed question of law and fact, as in Gaudin. He further
contends that the statutory language requires the government
to prove not only the existence of a contract or agreement, but
also that at least one federal inmate (and perhaps more,
depending on how “persons” is read) was in fact held in
custody at the facility at the time of the crime. We are
persuaded that the more natural reading is that the
government must simply prove there is an effective contract
or agreement to hold federal detainees in custody, and that
where, as here, the facts are undisputed, the trial court may
make this determination. See id.12

 11
    In his reply brief, Mujahid speculates without any evidentiary support
that the agreement may not have been with the “head” of the U.S.
Marshals Service, and that it may not have been in effect when the crimes
occurred. We conclude Mujahid waived these arguments by failing to
raise them before the district court and in his opening brief on appeal. See
Trigueros v. Adams, 658 F.3d 983, 988 (9th Cir. 2011) (“Ordinarily,
arguments not raised before the district court are waived on appeal.”);
Smith v. Marsh, 194 F.3d 1045, 1052 (9th Cir. 1999) (“[O]n appeal,
arguments not raised by a party in its opening brief are deemed waived.”).
 12
    Mujahid would have us treat the question of the existence of a contract
like the requirement in a federal bank robbery prosecution that the
government prove the bank is FDIC-insured to the jury, even if the facts
are undisputed. See United States v. James, 987 F.2d 648, 650 (9th Cir.
                    UNITED STATES V. MUJAHID                             19

    Moreover, even if we were to conclude it was error for the
district court to decide as a matter of law that the Anchorage
Correctional Complex is a facility in which persons are held
in custody pursuant to an agreement with the U.S. Marshals
Service, we would conclude that any error was harmless
based on the contract and testimony proffered by the
government at trial. See United States v. Thongsy, 577 F.3d
1036, 1043 (9th Cir. 2009) (“An error . . . omitting an
element of the offense in a jury instruction is harmless if it is
‘clear beyond a reasonable doubt that a rational jury would
have found the defendant guilty absent the error.’” (quoting
Neder v. United States, 527 U.S. 1, 18 (1999))).

    In sum, we hold that in prosecutions under 18 U.S.C.
§§ 2241, 2242, and 2244, the district court may determine as
a matter of law whether the facility at which the alleged crime
took place is one “in which persons are held in custody by
direction of or pursuant to a contract or agreement with the
head of any Federal department or agency.” The question


1993) (whether a bank is FDIC-insured is a question of fact for the jury).
But we cannot treat the question here as one of fact in all instances,
because we have held that—at least when facts are undisputed—contract
formation is a question of law. Chateau des Charmes Wines Ltd.,
328 F.3d at 530. Because that precedent resolves this case, we need not
determine whether the question here is always a question of law, as in our
recent decision in United States v. Zepeda, No. 10-10131, 2015 WL
4080164, at *1 (9th Cir. July 7, 2015) (en banc) (concluding that, under
the Indian Major Crimes Act, the trial judge should determine as a matter
of law whether a defendant’s alleged tribe is federally recognized, since
such recognition is “a political decision made solely by the federal
government and expressed in authoritative administrative documents”).
Although Zepeda may well suggest that the question here, like the
question there, can be decided by the trial court even if facts are disputed,
we need not resolve that issue. Nor do we need to resolve any apparent
tension between Zepeda and James.
20             UNITED STATES V. MUJAHID

whether the crime occurred at the facility must be submitted
to the jury, as it was here.

                     CONCLUSION

   For the foregoing reasons, we AFFIRM Mujahid’s
convictions.
