 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued January 12, 2018             Decided August 24, 2018

                        No. 16-3096

                UNITED STATES OF AMERICA,
                        APPELLEE

                              v.

 ALFREDO MOSQUERA-MURILLO, ALSO KNOWN AS ALFREDO
                LOPEZ-GUTIERREZ,
                   APPELLANT


            Consolidated with 16-3097, 16-3098


        Appeals from the United States District Court
                for the District of Columbia
                   (No. 1:13-cr-00134-3)
                   (No. 1:13-cr-00134-5)
                   (No. 1:13-cr-00134-4)


    Julia Fong Sheketoff, pro bono, argued the cause for
appellant. With her on the briefs were Louis K. Fisher and
Sparkle L. Sooknanan, pro bono, A.J. Kramer, Federal Public
Defender, and Richard K. Glibert and Carmen D. Hernandez,
appointed by the court.

    John M. Pellettieri, Attorney, U.S. Department of Justice,
argued the cause for appellee. With him on the brief were
                               2
Trevor N. McFadden, Deputy Assistant Attorney General, and
Adrienne L. Rose, Attorney. John Alex Romano, Attorney, and
Elizabeth Trosman, Assistant U.S. Attorney, entered
appearances.

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

    Opinion for the Court filed by Circuit Judge SRINIVASAN.

     SRINIVASAN, Circuit Judge: In June 2012, the United
States Coast Guard intercepted a Colombian vessel called the
Mistby, which was transporting cocaine and marijuana to
Panama. The three defendants in these consolidated cases
pleaded guilty to conspiring to distribute, and possess with
intent to distribute, the drugs on board the Mistby, in violation
of the Maritime Drug Law Enforcement Act (MDLEA), 46
U.S.C. § 70501 et seq., and the Controlled Substances Import
and Export Act, 21 U.S.C. § 951 et seq. Each defendant was
sentenced to 10 years of imprisonment.

     The defendants now appeal on two grounds. First, they
argue that the district court lacked subject-matter jurisdiction
over their prosecutions because they were not on board the
Mistby when it was intercepted. In the defendants’ view,
Colombia’s assent to U.S. jurisdiction over individuals
associated with the Mistby was limited to persons found on
board the vessel. Second, the defendants contend that their
offense of conviction is covered by the so-called safety-valve
provision, 18 U.S.C. § 3553(f). That provision, in certain
circumstances,      exempts       covered    offenses      from
mandatory-minimum sentences such as the 10-year sentences
imposed against the defendants.
                                3
     We conclude that the district court had subject-matter
jurisdiction over the defendants’ prosecutions, but that the
defendants’ offense is covered by the safety-valve provision.
We therefore vacate the defendants’ sentences and remand for
resentencing.

                                I.

     The Coast Guard first spotted the Mistby on the high seas
about 70 nautical miles off the coast of Panama. When the
Coast Guard approached, the Mistby fled, and its crew began
to dump cargo overboard. The cargo turned out to be 22 bales
of drugs, containing more than 220 kilograms of cocaine and
more than 120 kilograms of marijuana.

     The Coast Guard eventually overtook the Mistby and
boarded it to determine its nationality, at which point the
Mistby’s captain claimed the vessel was registered in
Colombia. The United States and Colombia have agreed by
treaty to “cooperate in combating illicit traffic by sea.”
Agreement to Suppress Illicit Traffic by Sea, Colom.-U.S., art.
2, Feb. 20, 1997, T.I.A.S. No. 12,835. Pursuant to that treaty,
the Coast Guard asked the Colombian Navy (i) to verify that
the Mistby was registered in Colombia, and (ii) to grant the
Coast Guard permission to search the vessel. See id. art. 7. The
Colombian Navy granted both requests. The Coast Guard then
searched the Mistby and arrested the people on board, but the
defendants were not among them.

     The next day, the Coast Guard asked the Colombian Navy
to confirm that, under Article 16 of the treaty, the United States
had jurisdiction over the Mistby. The Colombian Navy did so
on June 26, stating that, under the “agreement signed by the
governments of the United States and Colombia, [the United
States could] exercise their jurisdiction.” Ardila M. Hector,
                              4
Colombian Naval Operations Ctr., Response to Request for
Interpretation of Article 16(1) of the Maritime Agreement Col.-
U.S. (June 26, 2012) (formatting modified).

    The Coast Guard memorialized the Colombian Navy’s
response in a certification, which reads, in relevant part:

       On June 26, 2012, Colombian authorities
       confirmed and concurred with the United
       States’ interpretation of Article 16 of the
       Agreement, thereby waiving objection to the
       enforcement of United States law by the United
       States over the go-fast vessel MISTBY, all
       associated contraband, and persons on board.

Salvatore J. Fazio, U.S. Coast Guard, Certification for the
Maritime Drug Law Enforcement Act Case Involving Go-Fast
Vessel Mistby (Colombia) ¶ 4.e (Aug. 10, 2012) (hereinafter
Coast Guard Certification). “Accordingly,” the certification
concludes, “the Government of the United States determined
the go-fast vessel MISTBY was subject to the jurisdiction of
the United States pursuant to 46 U.S.C. § 70502(c)(1)(C).” Id.
¶ 4.f.

     Months    later,    the     three     defendants—Alfredo
Mosquera-Murillo, Antonio Moreno-Membache, and Joaquin
Chang-Rendon—were charged with conspiring to distribute,
and possess with intent to distribute, the drugs transported on
board the Mistby, in violation of 46 U.S.C. §§ 70503 and
70506(b), and 21 U.S.C. § 960(b)(1)(B) and (b)(2)(G). The
government’s theory as to each defendant’s involvement was
as follows: that Chang-Rendon (a civilian employee of the
Colombian Navy) knew the patrol routes of Colombian and
American law-enforcement vessels and passed that
information along to Mosquera-Murillo; that Mosquera-
                               5
Murillo in turn conveyed the information to the people
transporting the drugs; and that Moreno-Membache helped
move the drugs to the Colombian coast and then load them onto
the Mistby. At the time the defendants were charged, all three
of them were still in Colombia. The United States thus
requested extradition, which Colombia granted.

     Chang-Rendon and Mosquera-Murillo moved to dismiss
the indictment on the ground that the district court lacked
subject-matter jurisdiction over their prosecutions. The
government claimed that the district court had jurisdiction
under 46 U.S.C. § 70502(c)(1)(C), which applies if the vessel
on which an MDLEA offense was committed is “a vessel
registered in a foreign nation [and] that nation has consented or
waived objection to the enforcement of United States law by
the United States.” The defendants responded that, as shown
by the Coast Guard’s certification, Colombia waived objection
to the United States exercising jurisdiction over the “MISTBY,
all associated contraband, and persons on board”—but not
persons like the defendants who never set foot on the vessel.
Coast Guard Certification ¶ 4.e.

     The district court rejected that argument. The court held
that “a foreign government’s waiver of jurisdiction over a
particular vessel . . . establish[es a district] court’s
subject-matter jurisdiction over a subsequent prosecution of
any land-based co-conspirators.” United States v. Mosquera-
Murillo, 153 F. Supp. 3d 130, 158 (D.D.C. 2015). And in any
event, the court explained, the notion that Colombia had not
consented to the defendants’ prosecutions was difficult to
square “with the Colombian government’s subsequent
extradition of the defendants to the United States.” Id. at 159.

    The defendants then pleaded guilty. In their plea
agreements, they acknowledged that, given the quantity of
                               6
cocaine involved, the district court ordinarily would be
required to impose a mandatory-minimum sentence of 10 years
of imprisonment. See 21 U.S.C. § 960(b)(1)(B). But the
defendants reserved their rights (i) to argue they were eligible
for relief from that mandatory-minimum sentence under the
safety-valve provision, 18 U.S.C. § 3553(f), and (ii) to appeal
any contrary determination by the district court.

     The safety-valve provision states that sentencing relief is
available only “in the case of an offense under” 21 U.S.C.
§§ 841, 844, 846, 960 or 963. 18 U.S.C. § 3553(f). The
government argued that, because that list does not include any
provision of the MDLEA, the defendants’ offense was not
covered. The defendants responded that, because 21 U.S.C.
§ 960(b) supplied the penalties for their MDLEA violation, the
violation qualified as “an offense under” § 960.

     The district court agreed with the government, holding that
the defendants were ineligible for safety-valve relief. United
States v. Mosquera-Murillo, 172 F. Supp. 3d 24, 38 (D.D.C.
2016). The court thus sentenced each defendant to the
mandatory-minimum sentence of 10 years. This appeal
followed.

                               II.

    In this appeal, the defendants renew two arguments they
pressed unsuccessfully in the district court: that the district
court lacked subject-matter jurisdiction over their prosecutions,
and that they were eligible for safety-valve relief from the
10-year mandatory-minimum.

     Despite the defendants’ guilty pleas, they have not waived
or forfeited either argument. Challenges to a district court’s
subject-matter jurisdiction can never be waived by plea.
                                7
United States v. Miranda, 780 F.3d 1185, 1188 (D.C. Cir.
2015).       Nor can such challenges be forfeited, so
Moreno-Membache’s failure to contest subject-matter
jurisdiction in the district court does not preclude him from
raising the challenge now. And although sentencing challenges
can be waived, all three defendants entered conditional pleas
reserving their right to appeal the district court’s determination
that they were ineligible for safety-valve relief. See id. (citing
Fed. R. Crim. P. 11(a)(2)). We therefore consider both the
district court’s subject-matter jurisdiction and the defendants’
safety-valve eligibility.

                                A.

     The defendants initially argue that the district court lacked
subject-matter jurisdiction over their prosecutions. The
MDLEA criminalizes certain drug-related acts committed “on
board a covered vessel,” 46 U.S.C. § 70503(a), as well as
conspiracies to commit those acts, id. § 70506(b). We have
held that a defendant can violate the Act’s conspiracy provision
without personally setting foot “on board a covered vessel,” id.
§ 70503(a), so long as a co-conspirator commits a prohibited
act while “on board a covered vessel” and that act is attributable
to the defendant under ordinary principles of conspiracy law.
United States v. Ballestas, 795 F.3d 138, 145-46 (D.C. Cir.
2015); see Pinkerton v. United States, 328 U.S. 640, 647
(1946).

     The MDLEA defines “covered vessel” to include a vessel
“subject to the jurisdiction of the United States.” 46 U.S.C.
§ 70503(e)(1).       Relatedly, the MDLEA provides that
“[j]urisdiction of the United States with respect to a vessel . . .
is not an element of an offense” but is instead a “preliminary
question[] of law to be determined solely by the trial judge.”
Id. § 70504(a). Construing those provisions, we have held that,
                                8
“whether a vessel is ‘subject to the jurisdiction of the United
States’ is a [question] of subject-matter jurisdiction.” Miranda,
780 F.3d at 1192.

     In this case, the district court’s subject-matter jurisdiction
turns on the applicability of 46 U.S.C. § 70502(c)(1)(C), which
provides that a vessel is “subject to the jurisdiction of the
United States”—and thus is a “covered vessel”—if it is
“registered in a foreign nation [and] that nation has consented
or waived objection to the enforcement of United States law by
the United States.” Under the MDLEA, “[c]onsent or waiver
of objection by a foreign nation to the enforcement of United
States law by the United States . . . is proved conclusively by
certification of the [U.S.] Secretary of State or the Secretary’s
designee.” Id. § 70502(c)(2)(B).

     Here, the Secretary’s designee—the Coast Guard’s
Liaison Officer to the State Department’s Bureau of
International Narcotics and Law Enforcement Affairs—
certified that “Colombian authorities confirmed and concurred
with the United States’ interpretation of Article 16” of the
treaty between the two countries, “thereby waiving objection
to the enforcement of United States law by the United States
over the go-fast vessel MISTBY, all associated contraband, and
persons on board.” Coast Guard Certification ¶ 4.e. The
certification concludes that, “[a]ccordingly, the Government of
the United States determined the go-fast vessel MISTBY was
subject to the jurisdiction of the United States pursuant to 46
U.S.C. § 70502(c)(1)(C).” Id. ¶ 4.f.

    If, as the certification’s conclusion seems to say, the
Mistby is “subject to the jurisdiction of the United States
pursuant to 46 U.S.C. § 70502(c)(1)(C)” for purposes of all
MDLEA actions related to the vessel, id., then the district court
had subject-matter jurisdiction over the defendants’
                                9
prosecutions: in that event, the defendants’ “charged conduct
[would have] involved . . . one type of vessel ‘subject to the
jurisdiction of the United States,’” thus giving rise to subject-
matter jurisdiction, Miranda, 780 F.3d at 1197.

     The defendants argue, however, that the language of the
certification’s conclusion sweeps more broadly than the scope
of Colombia’s consent to U.S. jurisdiction. The defendants
submit that, if a foreign nation “consent[s] or waive[s]
objection to the enforcement of United States law” over a
vessel for purposes of proceedings against a specific person or
item of property, 46 U.S.C. § 70502(c)(1)(C), then the vessel
is “subject to the jurisdiction of the United States” for
proceedings against that person or property—but is not
“subject to the jurisdiction of the United States” for purposes
of other MDLEA proceedings. And that, the defendants say, is
exactly what occurred here.

     The defendants emphasize that, according to the Coast
Guard’s certification, Colombia “waiv[ed] objection to the
enforcement of United States law by the United States over the
go-fast vessel MISTBY, all associated contraband, and persons
on board.” Coast Guard Certification ¶ 4.e (emphasis added).
The reference to “persons on board,” the defendants assert,
means that Colombia denied consent to U.S. jurisdiction over
the Mistby for purposes of proceedings against persons (like
the defendants) who were not on board.

     We think the defendants misunderstand the Coast Guard’s
certification. Assuming the defendants are correct that a
foreign nation can grant consent to U.S. jurisdiction over a
vessel for some purposes but deny it for others, and assuming
also that a district court’s subject-matter jurisdiction under the
MDLEA would rise or fall correspondingly, we do not read the
                               10
Coast Guard’s certification to indicate that is what happened
here.

     The certification’s use of the term “persons on board,” id.
¶ 4.e, tracks the language of the statute, which discusses its
“prohibitions” in terms of individuals “on board a covered
vessel.” 46 U.S.C. § 70503(a). And the statute, as explained,
nonetheless reaches land-based co-conspirators because,
pursuant to “well-established principle[s] of conspiracy law,”
the acts of a person who is on board the vessel can be attributed
to a co-conspirator who remains on land. Ballestas, 795 F.3d
at 145-46. By the same token, the certification’s reference to
“persons on board” does not exclude persons who remain on
land: the acts of persons on board the Mistby would be
attributed to land-based co-conspirators like the defendants,
such that they too would effectively be considered to have
committed a prohibited act on board. The indictment
correspondingly charges the defendants with “conspir[ing],
and agree[ing] to . . . distribute, and possess with intent to
distribute,” cocaine and marijuana “on board a vessel subject
to the jurisdiction of the United States.” United States v.
Mosquera-Murillo, No. 13-cr-00134-03, Indictment at 2
(D.D.C. May 9, 2013), ECF No. 1 (emphasis added).

    That is not necessarily to say that a foreign nation is
incapable of consenting to the enforcement of U.S. law against
persons on board a vessel without also consenting to the
enforcement of U.S. law against land-based co-conspirators. In
theory, a foreign nation could say—and thus a certification
from the Coast Guard could report—that the nation consented
to U.S. jurisdiction over a vessel with respect to persons on
board, but denied consent with respect to co-conspirators not
on board.
                               11
     Here, though, the certification concludes by reporting,
without qualification, that “the Government of the United
States determined the go-fast vessel MISTBY was subject to
the jurisdiction of the United States pursuant to 46 U.S.C.
§ 70502(c)(1)(C).” Coast Guard Certification ¶ 4.f. And the
certification does not indicate that Colombia denied consent
with respect to any particular class of MDLEA proceedings—
including proceedings against co-conspirators not on board the
Mistby. Rather, the certification confirms that Colombia’s
consent to U.S. jurisdiction encompasses persons on board the
Mistby, whose conduct on board the vessel is attributable to co-
conspirators like the defendants.

      As a fallback argument, the defendants suggest that we
should look behind the Coast Guard’s certification and
examine Colombian law for ourselves. If we do so, the
defendants submit, we will find the following: (i) that the
treaty contemplates the application of U.S. law only if
Colombia’s domestic law allows for it, T.I.A.S. No. 12,835 art.
16; and (ii) that Colombian law envisions the application of
U.S. law only in the case of persons who are “on board” a
Colombian vessel. Código Penal (Criminal Code) [C. Pen.] tit.
II, § 217 (Colom.).

     Even assuming, arguendo, that we should scrutinize
Colombia’s domestic law, we note that one provision of that
law, introduced by the government in support of subject-matter
jurisdiction, says that a “punishable act shall be deemed to have
occurred” in “the place where the effect was produced or
should have been produced.” Id. § 201. That language mirrors
the conspiracy-law principle under which a land-based
conspirator in an enterprise that engages in prohibited conduct
on board a vessel will be treated as having himself participated
in the acts on board the vessel.
                              12
      Our understanding of the Coast Guard’s certification (and
of Colombian law) is reinforced by Colombia’s decision to
grant the United States’ extradition request concerning the
defendants. If Colombia had in fact intended to deny consent
to U.S. jurisdiction over the Mistby with respect to proceedings
against persons who never came on board the vessel, Colombia
could have given effect to that intention by declining to
extradite the defendants. Colombia did not do so, however.
That is not to say that the extradition itself gave rise to
subject-matter jurisdiction. It is instead to say that the
extradition fortifies our interpretation of the Coast Guard’s
earlier certification; and that certification substantiates the
district court’s subject-matter jurisdiction by demonstrating
that the Mistby is a “vessel subject to the jurisdiction of the
United States” for purposes of the defendants’ prosecutions. 46
U.S.C. § 70502(c)(1).

    In sum, we conclude that Colombia’s waiver of objection
to U.S. jurisdiction over the Mistby covers the defendants’
MDLEA prosecutions. The district court therefore had
subject-matter jurisdiction.

                              B.

    The defendants next argue that the district court erred by
holding that they were ineligible for safety-valve relief from
the 10-year mandatory-minimum term to which they were
sentenced. The safety-valve provision is entitled “Limitation
on applicability of statutory minimums in certain cases.” 18
U.S.C. § 3553(f). It provides that, “in the case of an offense
under” one of five enumerated provisions—21 U.S.C. §§ 841,
844, 846, 960, or 963—“the court shall impose a sentence
pursuant to [the sentencing] guidelines . . . without regard to
any statutory minimum sentence, if the court finds at
sentencing” that five specified requirements have been met.
                              13
     In these cases, the district court did not reach whether
those five requirements had been satisfied. Rather, the court
deemed the defendants ineligible for safety-valve relief at the
threshold, ruling that they had not been convicted of “an
offense under” any of the five enumerated provisions. The
court rejected the defendants’ argument that their cases
involved “an offense under” one of those provisions, namely
21 U.S.C. § 960.

     The sole question we face here is whether the defendants’
crime is “an offense under” § 960 within the meaning of the
safety-valve provision. 18 U.S.C. § 3553(f). Reviewing that
question of statutory interpretation de novo, see United States
v. Cordova, 806 F.3d 1085, 1098 (D.C. Cir. 2015) (per curiam),
we agree with the defendants: they were convicted of “an
offense under” § 960, and they therefore satisfy the threshold
condition for safety-valve eligibility.

     To see why, it is necessary to examine the relationship
between § 960 and the MDLEA provisions the defendants
pleaded guilty to violating. The MDLEA prohibits, as relevant
here, distributing, and possessing with intent to distribute,
drugs on board a covered vessel. 46 U.S.C. § 70503(a)(1). A
separate MDLEA provision prohibits “conspiring to violate
section 70503,” and establishes that anyone who so conspires
“is subject to the same penalties as provided for violating
section 70503.” Id. § 70506(b).

     What are those penalties? That is where 21 U.S.C. § 960
comes into play. Under the MDLEA, the first time a person
violates “paragraph (1) of section 70503(a),” she “shall be
punished as provided in . . . 21 U.S.C. [section] 960.” 46
U.S.C. § 70506(a). So the first time a person conspires to
violate § 70503(a)(1), she likewise “shall be punished as
provided in . . . 21 U.S.C. [section] 960.” Id. § 70506(a)-(b).
                               14
Because this was the defendants’ first conviction for conspiring
to violate § 70503(a)(1), § 960 supplied the penalties
applicable to their crime.

    Does that mean that the defendants’ crime is “an offense
under” § 960 for purposes of safety-valve eligibility? 18
U.S.C. § 3553(f). We conclude it does.

     As an initial matter, even if the precise meaning of the
phrase, “an offense under provision X” could be subject to
some debate at the margins, there is no doubt about the
following: a defendant’s case involves “an offense under”
provision X if the defendant has been convicted of violating
provision X. So here, there is no dispute that the defendants’
cases could be described as involving “an offense under” 46
U.S.C. §§ 70503(a)(1) and 70506(b). Indeed, the government,
throughout its briefs, describes the defendants as having been
“convicted of violating the MDLEA” or “violating a provision
of the MDLEA,” or, equivalently, as having been “convicted
under the MDLEA” or of “an offense under the MDLEA.”
E.g., Appellee’s Br. 25, 27, 31-32, 34, 41, 43.

    The defendants’ crime of conviction, though, involved
more than a violation of (or, equivalently, an offense under) the
MDLEA. It also involved a violation of (or, equivalently, an
offense under) 21 U.S.C. § 960. Offenses are defined by the
provisions that supply their elements. See Patterson v. New
York, 432 U.S. 197, 210 (1977). And here, the defendants’
offense draws certain elements from the relevant MDLEA
provisions, 46 U.S.C. §§ 70503(a)(1), 70506(b), and draws
other elements from 21 U.S.C. § 960.

     In particular, the MDLEA supplies the elements that make
the defendants’ conduct unlawful: (i) conspiring, (ii) to
intentionally or knowingly, (iii) distribute or possess with
                                 15
intent to distribute, (iv) a controlled substance, (v) while on
board a vessel.        46 U.S.C. §§ 70503(a)(1), 70506(b).
Meanwhile, § 960 supplies the offense elements of drug-type
and drug-quantity—5 or more kilograms of cocaine, and 100
or more kilograms of marijuana—which bear on the degree of
culpability and determine the statutory sentencing range. 21
U.S.C. § 960(b)(1)(B), (b)(2)(G).           In that light, the
defendants’ crime is “an offense under” both the MDLEA and
§ 960, drawing offense elements from each.

     The understanding that § 960 supplies offense elements
coheres with the rule of Apprendi v. New Jersey, 530 U.S. 466
(2000). Under Apprendi, “any fact that increases the
prescribed statutory maximum” penalty to which a defendant
is exposed amounts to an offense element that “must be
submitted to a jury, and proved beyond a reasonable doubt.”
Id. at 490; see Alleyne v. United States, 133 S. Ct. 2151, 2157
(2013) (plurality). The drug-type and drug-quantity elements
set out in § 960(b) qualify as elements for purposes of Apprendi
because they establish the maximum sentence. See 21 U.S.C.
§ 960(b)(1)(B)(ii) (“In the case of a violation . . . involving . . .
5 kilograms or more of . . . cocaine . . . the [defendant] shall be
sentenced to a term of imprisonment of . . . not more than
life.”); see also United States v. Fields, 251 F.3d 1041, 1043
(D.C. Cir. 2001). And because the drug-type and drug-quantity
criteria in § 960 constitute some of the elements of the
defendants’ offense (with the other elements supplied by the
MDLEA), their cases involve “an offense under” § 960 for
purposes of safety-valve eligibility. 18 U.S.C. § 3553(f).

     As further confirmation that § 960 supplies elements of the
defendants’ offense, the government’s indictment charged the
defendants with violating both the MDLEA and § 960, not just
the former. Specifically, the indictment charged the defendants
with one count of conspiring to distribute, and possess with
                              16
intent to distribute, 5 or more kilograms of cocaine and 100 or
more kilograms of marijuana on board a covered vessel, “all in
violation of Title 46, United States Code, Sections 70503 and
70506(b)” and “Title 21, United States Code, Sections
960(b)(1)(B) and (b)(2)(G).” United States v. Mosquera-
Murillo, No. 13-cr-00134-03, Indictment at 2 (D.D.C. May 9,
2013), ECF No. 1 (emphasis added).

     To the same effect, the government’s plea agreement with
each of the defendants stated that the defendant “agrees to
plead guilty” to the charged conduct just described, once again
“in violation of Title 46, United States Code, Sections 70503
and 70506(b)” and “Title 21, United States Code, Sections
960(b)(1)(B) and (b)(2)(G).” E.g., United States v. Mosquera-
Murrillo, No. 13-cr-00134-03, Plea Agreement at ¶ 1 (D.D.C.
Jan. 20, 2016), ECF No. 185. The judgments against the
defendants therefore pronounce that they were “adjudicated
guilty” of the charged offense in violation of both the relevant
MDLEA provisions and § 960(b). E.g., United States v.
Mosquera-Murillo, No. 13-cr-00134-03, Judgment at 1
(D.D.C. Aug. 1, 2016), ECF No. 250.

     Despite the government’s indictment and plea agreements
describing the defendants as having violated § 960, the
government now submits that the defendants were not
convicted of “an offense under” § 960 for purposes of
safety-valve eligibility. The government points out that § 960
consists of two subsections. The first, subsection (a), lists
certain “unlawful acts” by reference to drug offenses set out
elsewhere in the code—e.g., “bring[ing] or possess[ing] on
board a vessel, aircraft, or vehicle a controlled substance”
“contrary to section 955.” 21 U.S.C. § 960(a)(2). The second
subsection, subsection (b), sets out the penalties for the
offenses listed in subsection (a) based on drug-type and
drug-quantity—e.g., “[i]n the case of a violation of subsection
                              17
(a)” involving “1 kilogram or more of . . . heroin,” the “person
committing such violation shall be sentenced to a term of
imprisonment of not less than 10 years and not more than life.”
21 U.S.C. § 960(b)(1)(A).

     According to the government, the safety-valve provision’s
reference to “an offense under” § 960 means only those
specific offenses listed in § 960(a)—not other offenses defined
in part by the drug-type and drug-quantity elements set out in
§ 960(b). And because no MDLEA offense is listed in
§ 960(a), the government argues, the defendants’ cases do not
involve “an offense under” § 960 within the meaning of the
safety-valve provision.

    The government’s reading of the safety-valve provision is
unpersuasive. The statute speaks in terms of an “offense
under” § 960 without limitation—not an offense under only
§ 960(a). Plus, the structure of § 960 demonstrates that the
defendants’ crime qualifies as “an offense under” § 960 no less
than the crimes listed in § 960(a).

     Subsection (a) of § 960 does not lay out any element of—
and thus does not define in whole or in part—any criminal
offense. Instead, § 960(a) merely lists certain offenses
established elsewhere in the code. It does so for one reason: to
identify a set of offenses for which § 960(b) supplies the
drug-type and drug-quantity elements, and, accordingly, the
range of potential penalties.

    The MDLEA offense of which the defendants were
convicted interacts with § 960(b) in exactly the same way as
the offenses listed in § 960(a). Just as those offenses are
established outside of § 960 and “shall be punished as provided
in subsection (b)” of § 960, id. § 960(a), the MDLEA also
establishes offenses outside of § 960, which likewise are
                               18
punished under the penalty scheme set out in § 960(b). Indeed,
the MDLEA uses precisely the same wording in linking certain
of its offenses to § 960(b) as § 960(a) does in linking its listed
offenses to § 960(b): the MDLEA states that, for first-time
offenders of 46 U.S.C. § 70503(a)(1), the defendant “shall be
punished as provided in” § 960. 46 U.S.C. § 70506(a).
Compare id., with 21 U.S.C. § 960(a).

     If both the offenses listed in § 960(a) and the relevant
offenses under the MDLEA are (i) established outside of § 960,
and (ii) make use of the drug-type and drug-quantity elements
and associated penalties set forth in § 960(b), then there is no
reason to conclude—as the government would—that the
former qualify as “offenses under” § 960 for purpose of
safety-valve eligibility whereas the latter do not. Nothing in
the statutory text supports drawing such a distinction. Rather,
just as a person who commits one of the offenses listed in
§ 960(a) violates both the provision establishing the offense
(e.g., 21 U.S.C. § 955) and § 960(b), the defendants in these
cases violated both the MDLEA and § 960(b).                 The
government was right to describe the defendants’ offenses in
that manner in the indictment and plea agreements.

    In addition, treating the defendants as having violated
§ 960, and thus as eligible for safety-valve relief, would align
with Congress’s nearly unbroken pattern of setting identical
penalties for drug crimes committed in domestic waters and
drug crimes committed on the high seas. When Congress
criminalized opium possession on the high seas in 1914, it set
the maximum penalty at two years, which at the time was the
maximum penalty for importing opium into the United States.
Act of Jan. 17, 1914, Pub. L. No. 63-46, §§ 2, 4, 38 Stat. 275,
276. In 1922, Congress simultaneously raised the maximum
penalties for both offenses from two to ten years. Narcotic
Drugs Import and Export Act, Pub. L. No. 67-227, § 2(c), 42
                               19
Stat. 596, 596 (1922). Then, in 1951, Congress simultaneously
decreased the maximum penalties for both offenses from ten to
five years. Boggs Act, Pub. L. No. 82-255, § 2(c), 65 Stat. 767,
767 (1951).

     In 1970, Congress overhauled the drug code, repealing the
statutes that define the offenses discussed above, and
establishing a new prohibition—codified at 21 U.S.C. § 955—
against importing drugs via the customs waters of the United
States. Comprehensive Drug Abuse Prevention and Control
Act of 1970, Pub. L. No. 91-513, § 1007, 84 Stat. 1236, 1288.
Congress provided that the penalties applicable to that offense
were those set forth in 21 U.S.C. § 960. Id. § 1010, 84 Stat. at
1290. Shortly thereafter, Congress enacted what is now known
as the MDLEA, including its prohibition against possession
with intent to distribute on the high seas. Pub. L. No. 96-350,
§ 1, 94 Stat. 1159, 1159 (1980). And Congress provided that
§ 960 also supplied the penalties for that offense. Id. § 1(g)(1),
94 Stat. at 1159.

     In light of the century-long pattern of identical penalties
for drug offenses committed in domestic waters and on the high
seas, it is notable that, as both parties agree, offenders who
violate § 955 are eligible for safety-valve relief. 21 U.S.C.
§ 960(a) (listing violations of § 955 as offenses punishable
under § 960(b)). So if offenders who violate the MDLEA were
ineligible for safety-valve relief, then, by enacting the
safety-valve provision, Congress would have broken its
100-year pattern of penalty parity. We do not understand
Congress to have done so.

    Two other circuits have considered whether MDLEA
offenses penalized under § 960(b) qualify as “offenses under”
§ 960 for purposes of the safety-valve provision. Both courts
have concluded that such offenses do not qualify. See United
                               20
States v. Pertuz-Pertuz, 679 F.3d 1327, 1329 (11th Cir. 2012)
(per curiam); United States v. Gamboa-Cardenas, 508 F.3d
491, 496 (9th Cir. 2007). We respectfully reach the opposite
conclusion. Neither of those decisions expressly assesses
whether the drug-type and drug-quantity facts supplied by
§ 960(b) constitute offense elements, such that an MDLEA
offender penalized under § 960(b) should be considered
someone who has violated both the MDLEA and § 960. That
consideration, as we have explained, is pivotal to our
conclusion.

     Our decision today, we note finally, does not necessarily
resolve whether the safety valve covers a different provision to
which both parties have directed our attention: 21 U.S.C.
§ 860.      In defining the offense of “[d]istribution or
manufacturing in or near schools and colleges,” § 860
incorporates both the unlawful-act elements of 21 U.S.C.
§ 841(a) and the drug-type and drug-quantity elements of
§ 841(b). So one could argue that a violation of § 860 is an
“offense under” § 841, in which case offenders who violate
§ 860 would be eligible for safety-valve relief, given that the
safety valve lists § 841 as a covered provision. That said, § 860
restates in full the unlawful-act elements of § 841(a), and then
modifies the penalties prescribed by § 841(b) by doubling or
tripling them. That might mean that all the elements of an
§ 860 violation are supplied by § 860 itself, rather than by a
combination of § 860 and § 841. If that is the case, then
offenders who violate § 860 would be ineligible for safety-
valve relief, given that the safety valve does not list § 860 as a
covered provision. We need not decide the issue now; we
simply note that today’s decision does not necessarily answer
the § 860 question either way.
                             21
                    *    *   *    *   *

    For the foregoing reasons, we vacate the defendants’
sentences and remand for resentencing, at which the district
court should consider whether the defendants meet the five
remaining safety-valve requirements.

                                                So ordered.
