 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued April 1, 2016                    Decided April 7, 2017

                         No. 15-5199

 UNITED STATES ASSOCIATION OF REPTILE KEEPERS, INC., ET
                         AL.,
                     APPELLEES

                              v.

RYAN ZINKE, THE HONORABLE, IN HIS OFFICIAL CAPACITY AS
THE SECRETARY OF THE INTERIOR AND UNITED STATES FISH
               AND WILDLIFE SERVICE,
                    APPELLANTS

 HUMANE SOCIETY OF THE UNITED STATES AND CENTER FOR
               BIOLOGICAL DIVERSITY,
                     APPELLEES


        Appeal from the United States District Court
                for the District of Columbia
                    (No. 1:13-cv-02007)


    Emily A. Polachek, Attorney, U.S. Department of Justice,
argued the cause for federal appellants. With her on the briefs
were John C. Cruden, Assistant Attorney General, and
Meredith L. Flax, Attorney.

    George Kimbrell, Sr. was on the brief for amicus curiae
The Center for Invasive Species Prevention, Natural Areas
                               2
Association and the Wildlife Society in support of defendants-
appellants.

     David E. Frulla argued the cause for appellees U.S.
Association of Reptile Keepers, Inc., et al. With him on the
brief were Paul C. Rosenthal and Shaun M. Gehan.

    Collette L. Adkins and Anna E. Frostic were on the briefs
for defendant-intervenors/appellees The Humane Society of
the United States and Center for Biological Diversity.

    Before: TATEL, SRINIVASAN, and WILKINS, Circuit
Judges.

    Opinion for the Court filed by Circuit Judge SRINIVASAN.

     SRINIVASAN, Circuit Judge: A federal statute known as
the Lacey Act enables the Secretary of the Interior to designate
certain species of animals as injurious to humans, wildlife,
agriculture, horticulture, or forestry. When a species is
designated as injurious, the Act prohibits any importation of
the species into the United States or its possessions or
territories. 18 U.S.C. § 42(a)(1). The Act additionally bars
“any shipment” of the species “between the continental United
States, the District of Columbia, Hawaii, the Commonwealth
of Puerto Rico, or any possession of the United States.” Id.

    This case concerns the proper interpretation of the latter
provision, which we will refer to as the shipment clause. All
agree that the clause bars shipments of injurious species
between each of the listed jurisdictions—for instance,
shipments of animals between “Hawaii” and “the continental
United States,” or between “the Commonwealth of Puerto
Rico” and a “possession of the United States.” But what about
shipments between the states making up “the continental
                                3
United States”—for instance, shipments between Virginia and
Maryland? Does the clause prohibit those shipments as well?

    The government believes the answer is yes. It reads the
shipment clause not only to bar shipments between the
continental United States and the other listed jurisdictions, but
also to prohibit shipments between any of the 49 States
comprising the continental United States. The plaintiffs in this
case, individuals who breed and sell animals, disagree. In their
view, the shipment clause has no bearing on shipments of
animals from one of the 49 continental United States to
another.

     The district court sided with the plaintiffs’ interpretation.
The court thus preliminarily enjoined enforcement of a Fish
and Wildlife Service rule barring interstate shipments of two
species of snakes deemed to be injurious. We agree with the
district court’s understanding of the shipment clause. We
therefore affirm the court’s decision.

                                I.

                                A.

     Since its enactment in 1900, a principal “object and
purpose” of the Lacey Act has been “to regulate the
introduction of American or foreign birds or animals in
localities where they have not heretofore existed.” Lacey Act,
ch. 553, § 1, 31 Stat. 187, 188 (1900) (codified as amended at
16 U.S.C. § 701). In furtherance of that objective, the Act
established a criminal prohibition against importation into the
country of certain identified species and such additional species
“as the Secretary of Agriculture may from time to time declare
injurious to the interest of agriculture or horticulture.” 31 Stat.
                               4
at 188. That prohibition, which we will call the import clause,
later became codified at 18 U.S.C. § 42.

     In 1960, Congress sought “[t]o clarify certain provisions
of the Criminal Code relating to the importation or shipment of
injurious mammals, birds, amphibians, fish, and reptiles.” Pub.
L. No. 86-702, 74 Stat. 753, 753 (1960) (citing 18 U.S.C. § 42).
To that end, Congress enacted the clause directly in issue
here—the shipment clause—and appended it to the import
clause. The shipment clause, as noted at the outset of this
opinion, makes it illegal to ship injurious animals “between the
continental United States, the District of Columbia, Hawaii, the
Commonwealth of Puerto Rico, or any possession of the United
States.” 74 Stat. at 753-54 (now codified at 18 U.S.C. § 42(a)).

      The import and shipment clauses, in their current
formulations, read as follows (with the shipment clause
italicized for demarcation):

    The importation into the United States, any territory of the
    United States, the District of Columbia, the
    Commonwealth of Puerto Rico, or any possession of the
    United States, or any shipment between the continental
    United States, the District of Columbia, Hawaii, the
    Commonwealth of Puerto Rico, or any possession of the
    United States, of [enumerated species] and such other
    species . . . which the Secretary of the Interior may
    prescribe by regulation to be injurious to human beings, to
    the interests of agriculture, horticulture, forestry, or to
    wildlife or the wildlife resources of the United States, is
    hereby prohibited.

18 U.S.C. § 42(a)(1) (emphasis added).
                               5
      For some time after the shipment clause’s enactment in
1960, the Department of the Interior, in proposed rulemakings
and in testimony before Congress, understood the clause to
prohibit shipments of injurious animals between the listed
jurisdictions (for instance, shipments between “Hawaii” and
the “continental United States”) but not to bar interstate
shipments within the “continental United States” itself (for
instance, shipments between Kansas and Virginia). See U.S.
Ass’n of Reptile Keepers, Inc. v. Jewell, 103 F. Supp. 3d 133,
148-49 (D.D.C. 2015). The Department has since shifted
course. In recent years, whenever the Secretary of Interior,
acting through the Fish and Wildlife Service, promulgates a
rule designating a new species as injurious, the rule’s preamble
notes that the designation results in a prohibition against any
interstate transport of the species. See, e.g., 80 Fed. Reg.
12,702, 12,702 (Mar. 10, 2015). The government, that is, now
interprets the shipment clause to prohibit all interstate
shipments of injurious species: the clause, under that
interpretation, bars shipments not only between the
“continental United States” and “Hawaii” but also bars
shipments between the 49 continental States—thereby barring
all interstate shipments.

                                   B.

     On December 18, 2013, the United States Association of
Reptile Keepers and various individuals (ARK) filed the
underlying action in the district court, challenging a 2012 rule
in which the Fish and Wildlife Service designated as injurious
four species of snakes not in issue in this appeal. See 77 Fed.
Reg. 3,330 (Jan. 23, 2012). ARK argued that the Service lacks
authority under the Lacey Act to prohibit transportation of the
listed species between the 49 continental States. The shipment
clause, ARK argued, speaks solely to shipments from one listed
                                6
jurisdiction to another, and therefore does not address interstate
shipments within the continental United States itself.

     On March 10, 2015, the Service issued a rule designating
four additional species of snakes as injurious, including the two
species in issue here: the reticulated python and the green
anaconda. See 80 Fed. Reg. 12,702. Those two species are no
garden-variety snakes. Reticulated pythons can grow to a
length of more than 28 feet and have been known to eat
humans. Green anacondas are the world’s heaviest snakes,
attaining a weight in excess of 400 pounds and growing to
about 22 feet in length. Both species can reproduce via
parthenogenesis, a process by which numerous offspring can
hatch from a female’s unfertilized egg, enhancing the species’
ability to establish themselves in the wild and to resist efforts
to control their populations.

     ARK amended its complaint to include a challenge to the
2015 rule. ARK’s members breed and sell reticulated pythons
and green anacondas. Its members have legally acquired each
snake, but if the shipment clause prohibits all shipments of
listed injurious species from one continental State to another,
ARK’s members would face criminal penalties (a fine or up to
six months of imprisonment, see 18 U.S.C. § 42(b)) for
shipping the two species across state lines.

     ARK filed an application for a temporary restraining order
seeking to prohibit the 2015 rule from going into effect. The
district court converted ARK’s application for a temporary
restraining order into a motion for a preliminary injunction. On
the merits, the court concluded that the shipment clause does
not reach shipments between the 49 continental States, such
that the Service lacks authority to bar transport of the
designated snakes between those States. See Reptile Keepers,
103 F. Supp. 3d at 143-44, 159. The district court therefore
                               7
granted a preliminary injunction, and the government now
appeals.

                               II.

      To the extent the district court’s decision to enter a
preliminary injunction “hinges on questions of law, . . . our
review is essentially de novo.” Serono Labs., Inc. v. Shalala,
158 F.3d 1313, 1318 (D.C. Cir. 1998) (internal quotation marks
omitted). The central issue before us concerns the scope of the
Lacey Act’s shipment clause: does the clause prohibit
shipments of injurious animals from one of the 49 continental
States to another? We, like the district court, conclude that the
clause’s prohibition does not speak to shipments between the
continental States.

     At the outset, we note that the procedural context of this
appeal does not prevent us from definitively deciding the
merits of the shipment clause’s meaning. The district court’s
entry of a preliminary injunction turned on whether the party
seeking relief (here, ARK) is “likely” to succeed on the merits,
rather than on a final disposition of the merits. See Reptile
Keepers, 103 F. Supp. 3d at 141. Our review, however, “is not
confined” to the grant or denial of injunctive relief. See Ark.
Dairy Co-op Ass’n, Inc. v. U.S. Dep’t of Agric., 573 F.3d 815,
833 (D.C. Cir. 2009) (quoting Munaf v. Geren, 553 U.S. 674,
691 (2007)). When, as here, the ruling under review “rests
solely on a premise as to the applicable rule of law, and the
facts are established or of no controlling relevance,” we may
resolve the merits “even though the appeal is from the entry of
a preliminary injunction.” Thornburgh v. Am. Coll. of
Obstetricians and Gynecologists, 476 U.S. 747, 757 (1985),
overruled on other grounds by Planned Parenthood of Se.
Penn. v. Casey, 505 U.S. 833 (1992). We reach a definitive
judgment on the shipment clause’s meaning in order to “save
                                8
the parties the expense of future litigation.” See id. at 756-757;
see also 16 Charles A. Wright, Arthur R. Miller, Edward H.
Cooper, Federal Practice and Procedure § 3921.1 (3d ed.
2017).

                               A.

     Our interpretation of the shipment clause “begins where
all such inquiries must begin: with the language of the statute
itself.” United States v. Ron Pair Enters., Inc., 489 U.S. 235,
241 (1989). The shipment clause prohibits any shipment of an
injurious species “between the continental United States, the
District of Columbia, Hawaii, the Commonwealth of Puerto
Rico, or any possession of the United States.” 18 U.S.C.
§ 42(a)(1).

     The parties agree that the statute prohibits shipment of an
injurious species from any of the listed jurisdictions to any
other listed jurisdiction. We know, consequently, that there can
be no shipments between Hawaii and Puerto Rico, or between
Guam (a possession of the United States) and the District of
Columbia. We likewise know, with regard to “the continental
United States,” that there can be no shipments from the
continental United States to Hawaii (or vice versa), or from the
continental United States to Puerto Rico (or vice versa).

    While it is common ground that the shipment clause
prohibits shipments between the continental United States and
any of the other listed jurisdictions, what about shipments
between the 49 “continental United States” themselves—
between Virginia and Maryland, for instance? The government
submits that the shipment clause bars those shipments as well.
ARK argues otherwise. We agree with ARK.
                               9
     ARK’s interpretation of the shipment clause is “mandated
by the grammatical structure of the statute.” Ron Pair, 489
U.S. at 241. When the word “between” introduces multiple
items, it “expresses one-to-one relations” between the
identified items. Bryan A. Garner, Garner’s Modern American
Usage 101 (3d ed. 2009); see also Chicago Manual of Style
§ 5.220. While “between,” when used to introduce multiple
items, therefore speaks to relationships between—i.e.,
across—the listed items, it ordinarily expresses nothing about
relationships within any one of the listed items.

     Consider, for instance, a notice to travelers saying the
following: “Due to the weather, any flights between California
cities are cancelled.” That bulletin imparts information about
the status of flights within the sole listed item (“California
cities”)—i.e., information about flights from one California
city to another. Now, consider instead a bulletin which uses
“between” to introduce a list of two items rather than just the
one: “Due to the weather, any flights between California cities
and New York are cancelled.” That notice speaks in terms of
a one-to-one relationship between the two listed items: it
communicates that there will be no flights from California
cities (collectively) to New York, and vice versa. It says
nothing, however, about the effect of the weather on flights
within the first listed item alone—that is, flights between
California cities.

     The same is true of the shipment clause, which carries a
parallel structure. See 18 U.S.C. § 42(a)(1). Whereas the
hypothetical travel bulletin says that “any flights” between
“California cities” and “New York” are cancelled, the shipment
clause says that “any shipment” between “the continental
United States” and “Hawaii” is prohibited. Just as the travel
notice tells us something about flights between California cities
(collectively) and New York, while saying nothing about
                              10
flights between each California city, the shipment clause tells
us something about shipments between the continental United
States (collectively) and Hawaii, while saying nothing about
shipments between the 49 continental States.

      The shipment clause of course references not just the
“continental United States” and “Hawaii,” but also includes in
its list of jurisdictions “the Commonwealth of Puerto Rico,” the
“District of Columbia,” and “any possession of the United
States.” The use of “between” to introduce more than two
objects does not alter the proper understanding of the clause.
“Between has long been recognized as being perfectly
appropriate for more than two objects if multiple one-to-one
relationships are understood from the context.” Chicago
Manual of Style § 5.220; see Garner, supra, at 101-02. In such
a situation, in other words, “between” denotes that each listed
object shares a one-to-one relationship with each of the other
objects. It still indicates nothing, though, about relationships
within any of the listed objects itself.

     That is true, for instance, of the following observation:
“there are no games between National Football League teams,
Major League Baseball teams, and National Basketball
Association teams.” That sentence speaks in terms of multiple
one-to-one relationships—viz., the relationship of each of the
listed professional sports leagues to the other leagues. It
expresses that there are no games in which an NFL team plays
against an MLB team, no games in which an MLB team plays
against an NBA team, and no games in which an NBA team
plays against an NFL team. The sentence, however, tells us
nothing about relationships within any of the listed leagues. It
does not, for example, indicate that there are no games in which
an NFL team plays against another NFL team.
                              11
     The shipment clause operates in the same manner. It
addresses (and prohibits) shipments from each listed
jurisdiction to each of the other jurisdictions. It says nothing
about shipments within one of the listed jurisdictions (the
continental United States).

     The government sees substantial significance in the
shipment clause’s use of the disjunctive “or,” rather than the
conjunctive “and,” when enumerating the listed jurisdictions.
The clause, the government stresses, prohibits shipments
“between the continental United States, the District of
Columbia, Hawaii, the Commonwealth of Puerto Rico, or any
possession of the United States.” 18 U.S.C. § 42(a)(1)
(emphasis added). The word “or,” to the government, means
that the clause not only prohibits shipments from the
continental United States to the other jurisdictions (and vice
versa), but also bars shipments from any of the 49 continental
States to any other continental State.

     “Or” cannot do the work demanded of it by the
government. The use of “or” in a list introduced by “between”
is non-idiomatic. One commonly cited usage manual thus
observes that the “natural conjunction linking elements
introduced by between is and . . . , but or” is “occasionally
encountered and . . . always regrettable.” R.W. Burchfield, The
New Fowler’s Modern English Usage 107 (3d ed. 2000).

     The ordinary remedy for the “always regrettable” use of
“or” in connection with “between” is simply to read “or” as
“and.” Id.; see Garner, supra, at 103. A reference to a choice
“between payment in money or in kind” therefore is readily
understood to express a choice between payment in money and
in kind. Burchfield, supra, at 107 (emphasis altered). So, too,
with the shipment clause: the non-idiomatic “or” is best
                               12
understood as “and,” such that the use of “or” rather than “and”
should have no effect on the clause’s meaning.

     The word “or” in the shipment clause, regardless, could
not bear the specific weight given to it by the government. At
most, the non-idiomatic use of “or” in connection with a list of
objects introduced by “between” could give rise to ambiguity
about whether the statement speaks to one-to-one relationships
across the listed items or instead speaks to relationships within
each listed item. The government, however, reads the shipment
clause to prohibit both shipments across the listed jurisdictions
(between the continental United States and Hawaii, for
instance) and shipments within a listed jurisdiction (from one
continental State to another). There is no support for assigning
“between” double duty of that kind merely because it is paired
with “or.”

     Consider, for instance, a facsimile of the sports-league
example introduced earlier which states that “there are no
games between NFL teams or MLB teams.” If we read “or” as
“and,” then, as before, the statement would address games
between NFL teams and MLB teams, expressing that there are
no games across leagues in which an NFL team plays against
an MLB team. The statement would say nothing about games
within each league—i.e., games between one NFL team and
another. But even if we were to understand “or” to mean
something other than “and,” we would then read the statement
to say that there are no games between NFL teams or between
MLB teams. Under that alternative interpretation, the
statement would tell us that there are no games in which one
NFL team plays another, or in which one MLB team plays
another. But this time, while we would know something about
relationships within each league (games between two NFL
teams), we would know nothing about relationships across the
leagues (games between an NFL team and an MLB team).
                               13
     For our purposes, the critical point is that each of the two
alternative understandings of the “between/or” clause speaks
either to relationships across the listed objects or to
relationships within each listed object, but not to both. Here,
all parties (including the government) agree that the shipment
clause prohibits shipments across the listed jurisdictions—i.e.,
from the continental United States to Hawaii, and vice versa.
The clause, then, cannot also speak to shipments within the
continental United States itself—i.e., from one continental
State to another.

     That becomes particularly evident when taking into
account that the shipment clause’s listed jurisdictions include
singular (as opposed to plural) entities: Hawaii, Puerto Rico,
the District of Columbia, and any possession of the United
States. Even if one could read the phrase, “there are no games
between NFL teams or MLB teams,” to mean “there are no
games between NFL teams or between MLB teams,” that
reading is possible only because both objects of “between” in
that example are plural. No such interpretation is available
when the list of objects introduced by “between” includes
singular items. A statute barring “shipments between the
continental United States or Puerto Rico” cannot be read to
prohibit “shipments between the continental United States or
between Puerto Rico.” It would make no sense to speak in
terms of barring “shipments between Puerto Rico.”

    For those reasons, the shipment clause is best read—
indeed, can only be read—solely to prohibit shipments from
one listed jurisdiction to another. The clause does not speak to
shipments within the continental United States itself. That
understanding, for the reasons explained, holds true regardless
of whether “the continental United States” in the clause is
conceived of as a singular or plural item. Even if the latter, the
clause’s remaining listed jurisdictions are singular. The clause
                               14
thus must be understood to prohibit shipments across its listed
jurisdictions without addressing shipments within a particular
listed jurisdiction. The clause consequently does not speak to
shipments of injurious species from one continental State to
another.

     Because we see no ambiguity in the shipment clause’s
terms in this regard, we have no need to address the parties’
dispute about whether we should defer to the Fish and Wildlife
Service’s contrary interpretation of the relevant language. The
parties disagree on whether ordinary principles of Chevron
deference apply to an agency’s interpretation of a criminal
provision like the shipment clause. Chevron deference,
however, “come[s] into play” only when we must resolve
statutory ambiguity. See S. Cal. Edison Co. v. FERC, 195 F.3d
17, 23, 27 (D.C. Cir. 1999). Because we read the shipment
clause to be clear, we have no occasion to address whether we
would defer to the agency’s resolution of any ambiguous
statutory terms. See Chevron, U.S.A., Inc. v. Nat. Res. Def.
Council, Inc., 467 U.S. 837, 842-43 (1984).

                               B.

     Our interpretation of the shipment clause is consistent with
the evolution of the Lacey Act’s terms over time. Before the
addition of the shipment clause in 1960, the import clause—the
provision to which the shipment clause would be appended—
simply prohibited the “importation into the United States of”
injurious species. Act of June 25, 1948, ch. 645, 62 Stat. 683,
687 (1948). The “United States” for purposes of the Act
encompassed its territories (which at the time included Hawaii
and Puerto Rico), as well as its possessions. See 62 Stat. at 685.
The Act therefore prohibited imports from foreign countries
into the United States and its territories and possessions, but it
                               15
contained no distinct bar against transport of injurious species
to the country’s mainland from its territories or possessions.

     In 1960, Congress amended the Act in part by adding, to
the bar against imports “into the United States,” the shipment
clause’s prohibition against shipments “between the
continental United States, the District of Columbia, Hawaii, the
Commonwealth of Puerto Rico, or any possession of the United
States.” Pub. L. No. 86-702, 74 Stat. 753, 753 (1960). By
singling out the “continental United States” as a distinct object,
Congress manifested a desire to protect the mainland from
shipments of injurious species from Hawaii (which had just
become a state in 1959, see Pub. L. No. 86-3, 73 Stat. 4 (1959)),
from Puerto Rico, and from island possessions such as the
United States Virgin Islands and Guam.

     “[A]lthough we need not rely on legislative history given
the text’s clarity, we note that the history only supports our
interpretation” of the 1960 amendments. See Mohamad v.
Palestinian Auth., 132 S. Ct. 1702, 1710 (2012). The
Department of the Interior drafted the bill which eventually
became those amendments. The Assistant Director, Bureau of
Sport Fisheries and Wildlife, testified about the amendment on
the Department’s behalf at a House of Representatives
subcommittee hearing. In outlining the rationale for adding the
shipment clause, he stated that “we have broadened the
language a bit to prohibit the shipment between the Continental
United States and Hawaii, Puerto Rico, and the Virgin Islands
of the Mongoose, for this reason: Currently the Mongoose
occurs in Hawaii, Puerto Rico, and the Virgin Islands.” H.R.
10329 and H.R. 10598: Hearing Before the House Comm. on
the Judiciary, 86th Cong. 6 (1960) (statement of Lansing A.
                               16
Parker, Assistant Director of the Bureau of Sport Fisheries and
Wildlife, Department of the Interior).

     That description reinforces the conclusion we
independently draw from the text of the amendments: the
addition of the shipment clause enabled Congress to protect the
continental United States against the introduction of injurious
species found in Hawaii, Puerto Rico, and any United States
possession. The government, though, understands the clause
to do much more than that. It reads the clause not only to bar
shipments of injurious species into the continental United
States from Hawaii and the other jurisdictions (and vice versa),
but also to prohibit any shipments between the remaining 49
States. Had Congress desired to achieve the latter objective,
however, there would have been no need to reference Hawaii
and the continental United States separately. Rather, Congress
simply could have barred shipments between “any State”
(which by 1960 included Hawaii).

     In fact, Congress used precisely that formulation in a
neighboring provision of the Lacey Act. See 74 Stat. at 754.
The provision, which the parties refer to as the trade provision,
pertains to the transport of animals that have been illegally
obtained or taken. In the same 1960 amendments which added
the shipment clause, Congress also amended the trade
provision to prohibit carrying or transporting illegally obtained
animals “to or from any State, territory, the District of
Columbia, the Commonwealth of Puerto Rico, any possession
of the United States, or any foreign country.” Id. (emphasis
added) (codified as amended at 18 U.S.C. § 43, now codified
as further amended at 16 U.S.C. § 3372(a)(1)). That language
                              17
plainly prohibits interstate shipments of animals subject to the
trade provision.

     If Congress likewise wanted to address interstate
shipments of animals in the shipment clause, Congress could
have (and presumably would have) used parallel language
when enacting that clause in a neighboring section of the same
amendments. See 74 Stat. at 753. Congress instead referred
separately to “Hawaii” and the “continental United States” in
the shipment clause, manifesting a narrower concern to protect
the continental United States against the introduction of
injurious species found in Hawaii, Puerto Rico, or United
States possessions.

      The shipment clause, while specifically referencing those
jurisdictions (the “continental United States,” “Hawaii,” the
“Commonwealth of Puerto Rico,” and “any possession of the
United States”), also lists the “District of Columbia.” To the
government, the reference to the District of Columbia
necessarily means that the shipment clause prohibits all
interstate shipments. Why, the government asks, would
Congress bar shipments of injurious species between Virginia
and the District of Columbia while allowing shipments of the
same species between Virginia and Maryland? We are
unpersuaded by the government’s reliance on the clause’s
listing of the District of Columbia.

    For starters, under the government’s reading of the
shipment clause, the clause’s reference to the District of
Columbia would be superfluous, which we generally assume
Congress would not have intended. See, e.g., Duncan v.
Walker, 533 U.S. 167, 174 (2001). Congress defined the
phrase “continental United States” in a statute enacted by the
same Congress in the year before the 1960 addition of the
shipment clause. See Pub. L. No. 86-70, § 48, 73 Stat. 141, 154
                                18
(1959); see also 1 U.S.C. § 1 note. Under that definition,
“[w]henever the phrase ‘continental United States’ is used in
any law of the United States enacted after the date of the
enactment of this Act, it shall mean the 49 States on the North
American Continent and the District of Columbia, unless
otherwise expressly provided.” Id. (emphasis added). In light
of that definition, if, as the government urges, the shipment
clause already barred the shipment of injurious species between
the continental States, there would have been no need to list the
District of Columbia separately.

      The government, at any rate, is wrong to assume there
could be no reason for Congress to prohibit the shipment of
injurious animals from Virginia to the District without also
barring shipments from Virginia to Maryland.                   The
government’s argument to that effect overlooks Congress’s
special legislative relationship with the District.            The
Constitution grants Congress the power “[t]o exercise
exclusive Legislation in all Cases whatsoever, over such
District (not exceeding ten Miles square) as may . . . become
the Seat of the Government of the United States.” U.S. Const.
art. I, § 8, cl. 17. That is, “Congress, when it legislates for the
District, stands in the same relation to District residents as a
state legislature does to residents of its own state.” Banner v.
United States, 428 F.3d 303, 308 (D.C. Cir. 2005) (emphasis
omitted). That was particularly true when the shipment clause
came into being in 1960, more than a decade before the
enactment of the Home Rule Act (which delegated “certain
legislative powers to the government of the District of
Columbia”). Pub. L. No. 93-198, 87 Stat. 774, 777 (1973).

    Before the Home Rule Act, consequently, Congress alone
had the ability to establish an import ban for the District of
Columbia. Individual states, by contrast, could protect
themselves by enacting their own laws prohibiting the
                               19
importation into their borders of invasive species. See Maine
v. Taylor, 477 U.S. 131, 151-52 (1986). Indeed, a number of
states restrict or prohibit the importation of injurious species
into their territory, with some of those laws specifically cross-
referencing species deemed injurious under the Lacey Act.
See, e.g., Ala. Admin. Code r. 220-2-.26; Ark. Admin Code
002.00.1-09.11; Conn. Agencies Regs. § 26-55-6; 301 Ky.
Admin. Regs. 2:082; Mo. Code Regs. Ann. tit. 3 § 10-4.117;
Nev. Admin Code § 503.110; N.Y. Comp. Codes R. & Regs.
tit. 6, § 575.3; Or. Admin. R. 635-056-0050; 4 Va. Admin.
Code § 15-30-40. Congress evidently exercised its own unique
authority over the District of Columbia in the shipment clause
in an effort to afford the same protection to the District. If so,
that would explain why Congress protected the District against
shipments from Virginia while leaving Maryland to protect
itself against those shipments.

     The government presses various additional arguments
grounded in the Lacey Act’s history in support of its reading of
the shipment clause, none of which persuades us. For instance,
the government relies on the 1960 amendments to the
aforementioned trade provision. That provision, as noted,
pertains to the transport of animals that have been illegally
obtained or taken, including members of an injurious species
imported in violation of the import clause. Before the 1960
amendments, the trade provision barred any transport, delivery,
or shipment of such animals, including from one state to
another. See 18 U.S.C. § 43 (1948). The government
understands the 1960 amendments to have removed the trade
provision’s prohibition against interstate transport of illegally
imported animals, and to have reconstituted that bar in the
                               20
shipment clause as a prohibition against interstate shipment of
all injurious animals.

     The premise of the government’s argument is
misconceived. While Congress amended the language of the
trade provision in 1960, the provision retained its prohibition
against interstate transport of animals imported from a foreign
country in violation of the import clause. The trade provision,
as amended in 1960, prohibited “deliver[ing], carr[ying],
transport[ing], ship[ping] . . . or knowingly receiv[ing] for
shipment” (including across state lines) any animal “which was
captured, killed, taken, purchased, sold, or otherwise possessed
or transported in any manner contrary to any Act of Congress
or regulation issued pursuant thereto” or any state, territorial,
or foreign law. 18 U.S.C. § 43 (1960) (emphasis added). The
import clause was an “Act of Congress” banning importation
into the United States of any injurious species. 18 U.S.C. § 42
(1960). Consequently, as with the pre-amendment version of
the trade provision, the 1960 version made it unlawful to ship
interstate any injurious animal imported in violation of the
import clause.

     The government separately argues that Congress, in
actions since 1960, has either ratified the government’s present
interpretation of the shipment clause or has amended the statute
by implication so as to bring about that interpretation. The crux
of the government’s argument lies in a series of laws amending
the Lacey Act’s injurious-species list to include the zebra
mussel, brown tree snake, and bighead carp. See Pub. L. No.
101-646, § 1208, 104 Stat. 4761, 4772 (1990) (zebra mussel);
Pub. L. No. 102-237, § 1013(e), 105 Stat. 1818, 1901 (1991)
(brown tree snake); Pub. L. No. 111-307, § 2, 124 Stat. 3282,
3282 (2010) (bighead carp). By the time of those amendments,
as now, the Fish and Wildlife Service had been construing the
Lacey Act to bar all interstate transport of listed injurious
                               21
species. See, e.g., 54 Fed. Reg. 22,286, 22,287 (May 23, 1989).
The government highlights legislative history suggesting that
at least some members of Congress, perhaps informed by the
Service’s interpretation of the statute, thought the amendments
would criminalize interstate shipment of the newly listed
species.

     The government’s arguments cannot overcome the plain
text of the shipment clause. When, as here, “the law is plain,
subsequent reenactment does not constitute an adoption of a
previous administrative construction.”           Demarest v.
Manspeaker, 498 U.S. 184, 190 (1991). Similarly, we will not
understand Congress to have amended an act by implication
unless there is a “positive repugnancy” between the provisions
of the preexisting and newly enacted statutes, as well as
language manifesting Congress’s “considered determination”
of the ostensible change. Blanchette v. Conn. Gen. Ins. Corps.,
419 U.S. 102, 134 (1974) (alteration omitted) (quoting In re
Penn Cent. Transp. Co., 384 F. Supp. 895, 943 (Reg’l Rail Reorg.
Ct. 1974)). The government falls short on both scores here.

     Even if some members of Congress might have assumed
that the amendments to the list of injurious species would
criminalize all interstate shipments of zebra mussels, brown
tree snakes, and bighead carp, applying the shipment clause’s
original, and more circumscribed, prohibition would not be
“repugnant” to those amendments. As written, the statute
would still criminalize the future importation of those species
as well as the future shipment of the species between the
jurisdictions listed in the shipment clause. That effect is fully
consistent with Congress’s intent to regulate the newly listed
species. There is no evidence, moreover, that Congress
affirmatively considered the purported effect of its targeted
amendments on all injurious species under the Lacey Act.
                               22
     We therefore decline to conclude that Congress, by
implication, altered the meaning of the shipment clause’s terms
so as to criminalize the interstate shipment of every Lacey Act
species. Rather, the clause continues to mean what it has meant
since its enactment: it prohibits the shipment of injurious
species between the listed jurisdictions, including to and from
the continental United States, but it does not speak to shipments
between the 49 continental States.

                      *    *   *    *   *

     For the foregoing reasons, we affirm the district court’s
judgment and hold as a matter of law that the government lacks
authority under the shipment clause to prohibit shipments of
injurious species between the continental States.

                                                    So ordered.
