(Slip Opinion)              OCTOBER TERM, 2012                                       1

                                       Syllabus

         NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
       being done in connection with this case, at the time the opinion is issued.
       The syllabus constitutes no part of the opinion of the Court but has been
       prepared by the Reporter of Decisions for the convenience of the reader.
       See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.


SUPREME COURT OF THE UNITED STATES

                                       Syllabus

                 UNITED STATES v. KEBODEAUX

CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR
                  THE FIFTH CIRCUIT

       No. 12–418.      Argued April 17, 2013—Decided June 24, 2013
Respondent Kebodeaux was convicted by a special court-martial of a
  federal sex offense. After serving his sentence and receiving a bad
  conduct discharge from the Air Force, he moved to Texas where he
  registered with state authorities as a sex offender. Congress subse-
  quently enacted the Sex Offender Registration and Notification Act
  (SORNA), which requires federal sex offenders to register in the
  States where they live, study, and work, 42 U. S. C. §16913(a), and
  which applies to offenders who, when SORNA became law, had al-
  ready completed their sentences, 28 CFR §72.3. When Kebodeaux
  moved within Texas and failed to update his registration, the Federal
  Government prosecuted him under SORNA, and the District Court
  convicted him. The Fifth Circuit reversed, noting that, at the time of
  SORNA’s enactment, Kebodeaux had served his sentence and was no
  longer in any special relationship with the Federal Government. Be-
  lieving that Kebodeaux was not required to register under the pre-
  SORNA Jacob Wetterling Crimes Against Children and Sexually Vio-
  lent Offender Registration Act, the court found that he had been “un-
  conditionally” freed. That being so, the court held, the Federal Gov-
  ernment lacked the power under Article I’s Necessary and Proper
  Clause to regulate his intrastate movements.
Held: SORNA’s registration requirements as applied to Kebodeaux fall
 within the scope of Congress’ authority under the Necessary and
 Proper Clause. Pp. 3–12.
    (a) Contrary to the Fifth Circuit’s critical assumption that Ke-
 bodeaux’s release was unconditional, a full reading of the relevant
 statutes and regulations makes clear that at the time of his offense
 and conviction he was subject to the Wetterling Act, which imposed
 upon him registration requirements very similar to SORNA’s. See,
2                   UNITED STATES v. KEBODEAUX

                                  Syllabus

    e.g., 42 U. S. C. §§14072(i)(3)–(4). The fact that these federal-law re-
    quirements in part involved compliance with state-law requirements
    made them no less requirements of federal law. See generally United
    States v. Sharpnack, 355 U. S. 286, 293–294. Pp. 3–6.
       (b) Congress promulgated the Wetterling Act under authority
    granted by the Military Regulation Clause, Art. I, §8, cl. 14, and the
    Necessary and Proper Clause. The same power that authorized Con-
    gress to promulgate the Uniform Code of Military Justice and punish
    Kebodeaux’s crime also authorized Congress to make the civil regis-
    tration requirement at issue here a consequence of his conviction.
    And its decision to impose a civil registration requirement that would
    apply upon the release of an offender like Kebodeaux is eminently
    reasonable. See Smith v. Doe, 538 U. S. 84, 102–103. It was also en-
    tirely reasonable for Congress to have assigned a special role to the
    Federal Government in ensuring compliance with federal sex offend-
    er registration requirements. See Carr v. United States, 560 U. S.
    438, ___. Thus, Congress did not apply SORNA to an individual who
    had, prior to its enactment, been “unconditionally released,” but ra-
    ther to an individual already subject to federal registration require-
    ments enacted pursuant to the Military Regulation and Necessary
    and Proper Clauses. SORNA somewhat modified the applicable reg-
    istration requirements to which Kebodeaux was already subject, in
    order to make more uniform what had remained “a patchwork of fed-
    eral and 50 individual state registration requirements,” Reynolds v.
    United States, 565 U. S. ___, ___. No one here claims that these
    changes are unreasonable or that Congress could not reasonably have
    found them “necessary and proper” means for furthering its pre-
    existing registration ends. Pp. 6–12.
687 F. 3d 232, reversed and remanded.

  BREYER, J., delivered the opinion of the Court, in which KENNEDY,
GINSBURG, SOTOMAYOR, and KAGAN, JJ., joined. ROBERTS, C. J., and
ALITO, J., filed opinions concurring in the judgment. SCALIA, J., filed a
dissenting opinion. THOMAS, J., filed a dissenting opinion, in which
SCALIA, J., joined as to Parts I, II, and III–B.
                       Cite as: 570 U. S. ____ (2013)                              1

                            Opinion of the Court

    NOTICE: This opinion is subject to formal revision before publication in the
    preliminary print of the United States Reports. Readers are requested to
    notify the Reporter of Decisions, Supreme Court of the United States, Wash-
    ington, D. C. 20543, of any typographical or other formal errors, in order
    that corrections may be made before the preliminary print goes to press.


SUPREME COURT OF THE UNITED STATES
                                  _________________

                                  No. 12–418
                                  _________________


 UNITED STATES, PETITIONER v. ANTHONY JAMES
                 KEBODEAUX
 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
            APPEALS FOR THE FIFTH CIRCUIT
                                [June 24, 2013]

   JUSTICE BREYER delivered the opinion of the Court.
   In 1999 a special court-martial convicted Anthony Kebo-
deaux, a member of the United States Air Force, of a sex
offense. It imposed a sentence of three months’ imprison-
ment and a bad conduct discharge. In 2006, several years
after Kebodeaux had served his sentence and been dis-
charged, Congress enacted the Sex Offender Registration
and Notification Act (SORNA), 120 Stat. 590, 42 U. S. C.
§16901 et seq., a federal statute that requires those con-
victed of federal sex offenses to register in the States
where they live, study, and work. §16913(a); 18 U. S. C.
§2250(a). And, by regulation, the Federal Government
made clear that SORNA’s registration requirements ap-
ply to federal sex offenders who, when SORNA became
law, had already completed their sentences. 42 U. S. C.
§16913(d) (Attorney General’s authority to issue regula-
tions); 28 CFR §72.3 (2012) (regulation specifying applica-
tion to pre-SORNA offenders).
   We here must decide whether the Constitution’s Neces-
sary and Proper Clause grants Congress the power to
enact SORNA’s registration requirements and apply them
2             UNITED STATES v. KEBODEAUX

                    Opinion of the Court

to a federal offender who had completed his sentence prior
to the time of SORNA’s enactment. For purposes of an-
swering this question, we assume that Congress has com-
plied with the Constitution’s Ex Post Facto and Due
Process Clauses. See Smith v. Doe, 538 U. S. 84, 105–106
(2003) (upholding a similar Alaska statute against ex post
facto challenge); Supp. Brief for Kebodeaux on Rehearing
En Banc in No. 08–51185 (CA5) (not raising any Due
Process challenge); Brief for Respondent (same). We
conclude that the Necessary and Proper Clause grants
Congress adequate power to enact SORNA and to apply
it here.
                             I
   As we have just said, in 1999 a special court-martial
convicted Kebodeaux, then a member of the Air Force, of a
federal sex offense. He served his 3-month sentence; the
Air Force released him with a bad conduct discharge. And
then he moved to Texas. In 2004 Kebodeaux registered
as a sex offender with Texas state authorities. Brief for
Respondent 6–7. In 2006 Congress enacted SORNA. In
2007 Kebodeaux moved within Texas from San Antonio to
El Paso, updating his sex offender registration. App. to
Pet. for Cert. 167a–168a. But later that year he returned
to San Antonio without making the legally required sex-
offender registration changes. Id., at 169a. And the Fed-
eral Government, acting under SORNA, prosecuted
Kebodeaux for this last-mentioned SORNA registration
failure.
   A Federal District Court convicted Kebodeaux of having
violated SORNA. See 687 F. 3d 232, 234 (CA5 2012) (en
banc). On appeal a panel of the United States Court of
Appeals for the Fifth Circuit initially upheld the convic-
tion. 647 F. 3d 137 (2011) (per curiam). But the Circuit
then heard the appeal en banc and, by a vote of 10 to 6,
reversed. 687 F. 3d, at 234. The court stated that, by the
                 Cite as: 570 U. S. ____ (2013)            3

                     Opinion of the Court

time Congress enacted SORNA, Kebodeaux had “fully
served” his sex-offense sentence; he was “no longer in
federal custody, in the military, under any sort of super-
vised release or parole, or in any other special relationship
with the federal government.” Ibid.
    The court recognized that, even before SORNA, federal
law required certain federal sex offenders to register. Id.,
at 235, n. 4. See Jacob Wetterling Crimes Against Chil-
dren and Sexually Violent Offender Registration Act,
§170101, 108 Stat. 2038–2042. But it believed that
the pre-SORNA federal registration requirements did not
apply to Kebodeaux. 687 F. 3d, at 235, n. 4. Hence, in the
Circuit’s view, Kebodeaux had been “unconditionally let
. . . free.” Id., at 234. And, that being so, the Federal
Government lacked the power under Article I’s Necessary
and Proper Clause to regulate through registration Kebo-
deaux’s intrastate movements. Id., at 234–235. In
particular, the court said that after “the federal govern-
ment has unconditionally let a person free . . . the fact
that he once committed a crime is not a jurisdictional
basis for subsequent regulation and possible criminal
prosecution.” Ibid.
    The Solicitor General sought certiorari. And, in light of
the fact that a Federal Court of Appeals has held a federal
statute unconstitutional, we granted the petition. See,
e.g., United States v. Morrison, 529 U. S. 598, 605 (2000);
United States v. Edge Broadcasting Co., 509 U. S. 418, 425
(1993).
                             II
  We do not agree with the Circuit’s conclusion. And, in
explaining our reasons, we need not go much further than
the Circuit’s critical assumption that Kebodeaux’s release
was “unconditional,” i.e., that after Kebodeaux’s release,
he was not in “any . . . special relationship with the fed-
eral government.” 687 F. 3d, at 234. To the contrary, the
4              UNITED STATES v. KEBODEAUX

                      Opinion of the Court

Solicitor General, tracing through a complex set of statu-
tory cross-references, has pointed out that at the time of
his offense and conviction Kebodeaux was subject to the
federal Wetterling Act, an Act that imposed upon him
registration requirements very similar to those that
SORNA later mandated. Brief for United States 18–29.
   Congress enacted the Wetterling Act in 1994 and up-
dated it several times prior to Kebodeaux’s offense. Like
SORNA, it used the federal spending power to encourage
States to adopt sex offender registration laws. 42 U. S. C.
§14071(i) (2000 ed.); Smith, supra, at 89–90.             Like
SORNA, it applied to those who committed federal sex
crimes. §14071(b)(7)(A). And like SORNA, it imposed
federal penalties upon federal sex offenders who failed to
register in the States in which they lived, worked, and
studied. §§14072(i)(3)–(4).
   In particular, §14072(i)(3) imposed federal criminal
penalties upon any “person who is . . . described in section
4042(c)(4) of title 18, and knowingly fails to register in any
State in which the person resides.” The cross-referenced
§4042(c)(4) said that a “person is described in this para-
graph if the person was convicted of ” certain enumerated
offenses or “[a]ny other offense designated by the Attorney
General as a sexual offense for purposes of this subsec-
tion.” 18 U. S. C. §4042(c)(4). In 1998 the Attorney Gen-
eral “delegated this authority [to designate sex offenses] to
the Director of the Bureau of Prisons.” Dept. of Justice,
Bureau of Prisons, Designation of Offenses Subject to Sex
Offender Release Notification, 63 Fed. Reg. 69386. And
that same year the Director of the Bureau of Prisons
“designate[d]” the offense of which Kebodeaux was con-
victed, namely the military offense of “carnal knowledge”
as set forth in Article 120(B) of the Code of Military Jus-
tice. Id., at 69387 See 28 CFR §571.72(b)(2) (1999). A full
reading of these documents makes clear that, contrary
to Kebodeaux’s contention, the relevant penalty applied to
                 Cite as: 570 U. S. ____ (2013)           5

                     Opinion of the Court

crimes committed by military personnel.
   Moreover, a different Wetterling Act section imposed
federal criminal penalties upon any “person who is . . .
sentenced by a court martial for conduct in a category
specified by the Secretary of Defense under section
115(a)(8)(C) of title I of Public Law 105–119, and know-
ingly fails to register in any State in which the person
resides.” 42 U. S. C. §14072(i)(4) (2000 ed.). The cross-
referenced section, §115(a)(8)(C), said that the “Secretary
of Defense shall specify categories of conduct punishable
under the Uniform Code of Military Justice which encom-
pass a range of conduct comparable to that described in
[certain provisions of the Violent Crime Control and Law
Enforcement Act of 1994], and such other conduct as the
Secretary deems appropriate.” 1998 Appropriations Act,
§115(a)(8)(C)(i), 111 Stat. 2466. See note following 10
U. S. C. §951 (2000 ed.). The Secretary had delegated
certain types of authority, such as this last mentioned
“deem[ing]” authority, to an Assistant Secretary of De-
fense. DoD Directive 5124.5, p. 4 (Oct. 31, 1994). And in
December 1998 an Assistant Secretary, acting pursuant to
this authority, published a list of military crimes that
included the crime of which Kebodeaux was convicted,
namely Article 120(B) of the Uniform Code of Military
Justice. App. to Pet. for Cert. 171a–175a. The provision
added that “[c]onvictions . . . shall trigger requirements
to notify state and local law enforcement agencies and to
provide information to inmates concerning sex offender
registration requirements.” Id., at 175a. And, the provi-
sion says (contrary to Kebodeaux’s reading, Brief for
Respondent 57), that it shall “take effect immediately.”
It contains no expiration date. App. to Pet. for Cert. 175a.
   We are not aware of any plausible counterargument to
the obvious conclusion, namely that as of the time of Kebo-
deaux’s offense, conviction and release from federal
custody, these Wetterling Act provisions applied to Kebo-
6              UNITED STATES v. KEBODEAUX

                     Opinion of the Court

deaux and imposed upon him registration requirements
very similar to those that SORNA later imposed. Con-
trary to what the Court of Appeals may have believed, the
fact that the federal law’s requirements in part involved
compliance with state-law requirements made them no
less requirements of federal law. See generally United
States v. Sharpnack, 355 U. S. 286, 293–294 (1958) (Con-
gress has the power to adopt as federal law the laws of a
State and to apply them in federal enclaves); Gibbons v.
Ogden, 9 Wheat. 1, 207–208 (1824) (“Although Congress
cannot enable a State to legislate, Congress may adopt the
provisions of a State on any subject. . . . The act [adopts
state systems for regulation of pilots] and gives [them] the
same validity as if its provisions had been specially made
by Congress”).
                             III
  Both the Court of Appeals and Kebodeaux come close to
conceding that if, as of the time of Kebodeaux’s offense,
he was subject to a federal registration requirement, then
the Necessary and Proper Clause authorized Congress to
modify the requirement as in SORNA and to apply the
modified requirement to Kebodeaux. See 687 F. 3d, at
234–235, and n. 4; Tr. of Oral Arg. 38–39. And we believe
they would be right to make this concession.
  No one here claims that the Wetterling Act, as applied
to military sex offenders like Kebodeaux, falls outside the
scope of the Necessary and Proper Clause. And it is
difficult to see how anyone could persuasively do so. The
Constitution explicitly grants Congress the power to
“make Rules for the . . . Regulation of the land and naval
Forces.” Art. I, §8, cl. 14. And, in the Necessary and
Proper Clause itself, it grants Congress the power to
“make all Laws which shall be necessary and proper for
carrying into Execution the foregoing Powers” and “all
other Powers” that the Constitution vests “in the Govern-
                 Cite as: 570 U. S. ____ (2013)            7

                     Opinion of the Court

ment of the United States, or in any Department or Officer
thereof.” Id., cl. 18.
  The scope of the Necessary and Proper Clause is broad.
In words that have come to define that scope Chief Justice
Marshall long ago wrote:
    “Let the end be legitimate, let it be within the scope of
    the constitution, and all means which are appropriate,
    which are plainly adapted to that end, which are not
    prohibited, but consist with the letter and spirit of the
    constitution, are constitutional.” McCulloch v. Mary-
    land, 4 Wheat. 316, 421 (1819).
As we have come to understand these words and the
provision they explain, they “leav[e] to Congress a large
discretion as to the means that may be employed in exe-
cuting a given power.” Lottery Case, 188 U. S. 321, 355
(1903). See Morrison, 529 U. S., at 607. The Clause al-
lows Congress to “adopt any means, appearing to it most
eligible and appropriate, which are adapted to the end to
be accomplished and consistent with the letter and spirit
of the Constitution.” James Everard’s Breweries v. Day,
265 U. S. 545, 559 (1924).
   The Constitution, for example, makes few explicit refer-
ences to federal criminal law, but the Necessary and
Proper Clause nonetheless authorizes Congress, in the im-
plementation of other explicit powers, to create federal
crimes, to confine offenders to prison, to hire guards and
other prison personnel, to provide prisoners with medical
care and educational training, to ensure the safety of those
who may come into contact with prisoners, to ensure the
public’s safety through systems of parole and supervised
release, and, where a federal prisoner’s mental condition
so requires, to confine that prisoner civilly after the expi-
ration of his or her term of imprisonment. See United
States v. Comstock, 560 U. S. 126, 136–137 (2010).
   Here, under the authority granted to it by the Military
8              UNITED STATES v. KEBODEAUX

                     Opinion of the Court

Regulation and Necessary and Proper Clauses, Congress
could promulgate the Uniform Code of Military Justice. It
could specify that the sex offense of which Kebodeaux was
convicted was a military crime under that Code. It could
punish that crime through imprisonment and by placing
conditions upon Kebodeaux’s release. And it could make
the civil registration requirement at issue here a conse-
quence of Kebodeaux’s offense and conviction. This civil
requirement, while not a specific condition of Kebodeaux’s
release, was in place at the time Kebodeaux committed his
offense, and was a consequence of his violation of federal
law.
  And Congress’ decision to impose such a civil require-
ment that would apply upon the release of an offender like
Kebodeaux is eminently reasonable. Congress could rea-
sonably conclude that registration requirements applied to
federal sex offenders after their release can help protect
the public from those federal sex offenders and alleviate
public safety concerns. See Smith, 538 U. S., at 102–103
(sex offender registration has “a legitimate nonpunitive
purpose of ‘public safety, which is advanced by alerting the
public to the risk of sex offenders in their community’ ”).
There is evidence that recidivism rates among sex offend-
ers are higher than the average for other types of crimi-
nals. See Dept. of Justice, Bureau of Justice Statistics,
P. Langan, E. Schmitt, & M. Durose, Recidivism of Sex
Offenders Released in 1994, p. 1 (Nov. 2003) (reporting
that compared to non-sex offenders, released sex offenders
were four times more likely to be rearrested for a sex
crime, and that within the first three years following
release 5.3% of released sex offenders were rearrested for
a sex crime). There is also conflicting evidence on the
point. Cf. R. Tewsbury, W. Jennings, & K. Zgoba, Final
Report on Sex Offenders: Recidivism and Collateral Con-
sequences (Sept. 2011) (concluding that sex offenders have
relatively low rates of recidivism, and that registration
                 Cite as: 570 U. S. ____ (2013)            9

                     Opinion of the Court

requirements have limited observable benefits regarding
recidivism). But the Clause gives Congress the power to
weigh the evidence and to reach a rational conclusion, for
example, that safety needs justify postrelease registration
rules. See Lambert v. Yellowley, 272 U. S. 581, 594–
595 (1926) (upholding congressional statute limiting the
amount of spirituous liquor that may be prescribed by
a physician, and noting that Congress’ “finding [regard-
ing the appropriate amount], in the presence of the well-
known diverging opinions of physicians, cannot be regarded
as arbitrary or without a reasonable basis”). See also
Gonzales v. Raich, 545 U. S. 1, 22 (2005) (“In assessing the
scope of Congress’ authority under the Commerce Clause,
we stress that the task before us is a modest one. We need
not determine whether respondents’ activities, taken in the
aggregate, substantially affect interstate commerce in
fact, but only whether a ‘rational basis’ exists for so con-
cluding”). See also H. R. Rep. No. 109–218, pt. 1, pp. 22,
23 (2005) (House Report) (citing statistics compiled by the
Justice Department as support for SORNA’s sex offender
registration regime).
  At the same time, “it is entirely reasonable for Congress
to have assigned the Federal Government a special role in
ensuring compliance with SORNA’s registration require-
ments by federal sex offenders—persons who typically
would have spent time under federal criminal supervi-
sion.” Carr v. United States, 560 U. S. 438, ___ (2010) (slip
op., at 12). The Federal Government has long kept track
of former federal prisoners through probation, parole, and
supervised release in part to prevent further crimes there-
by protecting the public against the risk of recidivism. See
Parole Act, 36 Stat. 819; Probation Act, ch. 521, 43 Stat.
1259; Sentencing Reform Act of 1984, ch. II, 98 Stat. 1987.
See also 1 N. Cohen, The Law of Probation and Parole
§§7:3, 7:4 (2d ed. 1999) (principal purposes of postrelease
conditions are to rehabilitate the convict, thus preventing
10             UNITED STATES v. KEBODEAUX

                      Opinion of the Court

him from recidivating, and to protect the public). Neither,
as of 1994, was registration particularly novel, for by then
States had implemented similar requirements for close to
half a century. See W. Logan, Knowledge as Power: Crim-
inal Registration and Community Notification Laws in
America 30–31 (2009). Moreover, the Wetterling Act took
state interests into account by, for the most part, requiring
released federal offenders to register in accordance with
state law. At the same time, the Wetterling Act’s re-
quirements were reasonably narrow and precise, tying
time limits to the type of sex offense, incorporating state-
law details, and relating penalties for violations to the
sex crime initially at issue. See 42 U. S. C. §14071(b)
(2000 ed.).
   The upshot is that here Congress did not apply SORNA
to an individual who had, prior to SORNA’s enactment,
been “unconditionally released,” i.e., a person who was not
in “any . . . special relationship with the federal govern-
ment,” but rather to an individual already subject to fed-
eral registration requirements that were themselves a
valid exercise of federal power under the Military Regula-
tion and Necessary and Proper Clauses. But cf. post, at 1
(SCALIA, J., dissenting).
   SORNA, enacted after Kebodeaux’s release, somewhat
modified the applicable registration requirements. In gen-
eral, SORNA provided more detailed definitions of sex
offenses, described in greater detail the nature of the
information registrants must provide, and imposed some-
what different limits upon the length of time that regis-
tration must continue and the frequency with which
offenders must update their registration. 42 U. S. C. §§16911,
16913–16916 (2006 ed. and Supp. V). But the statute, like
the Wetterling Act, used Spending Clause grants to en-
courage States to adopt its uniform definitions and re-
quirements. It did not insist that the States do so. See
§§16925(a), (d) (2006 ed.) (“The provisions of this subchap-
                  Cite as: 570 U. S. ____ (2013)           11

                      Opinion of the Court

ter that are cast as directions to jurisdictions or their
officials constitute, in relation to States, only conditions
required to avoid the reduction of Federal funding under
this section”).
  As applied to an individual already subject to the Wet-
terling Act like Kebodeaux, SORNA makes few changes.
In particular, SORNA modified the time limitations for a
sex offender who moves to update his registration to with-
in three business days of the move from both seven days
before and seven days after the move, as required by the
Texas law enforced under the Wetterling Act. Compare 42
U. S. C. §16913(c) with App. to Pet. for Cert. 167a–168a.
SORNA also increased the federal penalty for a federal
offender’s registration violation to a maximum of 10 years
from a maximum of 1 year for a first offense. Compare
18 U. S. C. §2250(a) with 42 U. S. C. §14072(i) (2000
ed.). Kebodeaux was sentenced to one year and one day
of imprisonment. For purposes of federal law, SORNA re-
duced the duration of Kebodeaux’s registration require-
ment to 25 years from the lifetime requirement imposed
by Texas law, compare 42 U. S. C. §16915(a) (2006 ed.)
with App. to Pet. for Cert. 167a, and reduced the frequency
with which Kebodeaux must update his registration to
every six months from every 90 days as imposed by Texas
law, compare 42 U. S. C. §16916(2) with App. to Pet. for
Cert. 167a. And as far as we can tell, while SORNA pun-
ishes violations of its requirements (instead of violations of
state law), the Federal Government has prosecuted a sex
offender for violating SORNA only when that offender also
violated state-registration requirements.
  SORNA’s general changes were designed to make more
uniform what had remained “a patchwork of federal and
50 individual state registration systems,” Reynolds v.
United States, 565 U. S. ___, ___ (2012) (slip op., at 2),
with “loopholes and deficiencies” that had resulted in an
estimated 100,000 sex offenders becoming “missing” or
12             UNITED STATES v. KEBODEAUX

                     Opinion of the Court

“lost,” House Report 20, 26. See S. Rep. No. 109–369,
pp. 16–17 (2006). See also Jinks v. Richland County, 538
U. S. 456, 462–463 (2003) (holding that a statute is au-
thorized by the Necessary and Proper Clause when it
“provides an alternative to [otherwise] unsatisfactory
options” that are “obviously inefficient”). SORNA’s more
specific changes reflect Congress’ determination that the
statute, changed in respect to frequency, penalties, and
other details, will keep track of more offenders and will
encourage States themselves to adopt its uniform stand-
ards. No one here claims that these changes are unrea-
sonable or that Congress could not reasonably have found
them “necessary and proper” means for furthering its pre-
existing registration ends.
   We conclude that the SORNA changes as applied to
Kebodeaux fall within the scope Congress’ authority under
the Military Regulation and Necessary and Proper Clauses.
The Fifth Circuit’s judgment to the contrary is reversed,
and the case is remanded for further proceedings consistent
with this opinion.
                                            It is so ordered.
                  Cite as: 570 U. S. ____ (2013)            1

              ROBERTS, C. J., concurring in judgment

SUPREME COURT OF THE UNITED STATES
                           _________________

                           No. 12–418
                           _________________


 UNITED STATES, PETITIONER v. ANTHONY JAMES
                 KEBODEAUX
 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
            APPEALS FOR THE FIFTH CIRCUIT
                         [June 24, 2013]

   CHIEF JUSTICE ROBERTS, concurring in the judgment.
   I agree with the Court that Congress had the power,
under the Military Regulation and Necessary and Proper
Clauses of Article I, to require Anthony Kebodeaux to
register as a sex offender. The majority, having estab-
lished that premise and thus resolved the case before us,
nevertheless goes on to discuss the general public safety
benefits of the registration requirement. Ante, at 8–10.
Because that analysis is beside the point in this case, I con-
cur in the judgment only.
   While serving in the Air Force, Kebodeaux violated the
Uniform Code of Military Justice by having sexual rela-
tions with a minor. A special court-martial convicted him.
As relevant here, that conviction had two consequences:
First, Kebodeaux was sentenced to confinement for three
months. And second, as the majority describes, he was
required to register as a sex offender with the State in
which he resided and keep that registration current; fail-
ure to do so would subject him to federal criminal penal-
ties. Ante, at 4–6.
   In the same way that Congress undoubtedly had the au-
thority to impose the first consequence for a violation of
military rules, it also had the authority to impose the
second. The Constitution gives Congress the power “[t]o
make Rules for the Government and Regulation of the
2             UNITED STATES v. KEBODEAUX

             ROBERTS, C. J., concurring in judgment

land and naval Forces.” Art. I, §8, cl. 14. And, under
the Necessary and Proper Clause, Congress can give those
rules force by imposing consequences on members of the
military who disobey them. See McCulloch v. Maryland, 4
Wheat. 316, 416 (1819) (“All admit that the government
may, legitimately, punish any violation of its laws; and
yet, this is not among the enumerated powers of Con-
gress.”). A servicemember will be less likely to violate a
relevant military regulation if he knows that, having done
so, he will be required to register as a sex offender years
into the future.
   It is this power, the power to regulate the conduct of
members of the military by imposing consequences for
their violations of military law, that supports application
of the federal registration obligation to Kebodeaux. As the
Court explains, the Wetterling Act was in force when
Kebodeaux committed the original offense, and applied to
him as soon as the special court-martial rendered its
verdict. See ante, at 5–6. Congress later, in enacting the
Sex Offender Registration and Notification Act (SORNA),
modified the registration regime in place under the Wet-
terling Act. But as applied to Kebodeaux here (the rele-
vant inquiry in this as-applied challenge), those changes
were insignificant; their only effect was that Kebodeaux
received a day more than he could have received for the
same conduct had the Wetterling Act remained in force.
See ante, at 11 (describing SORNA’s effect on Kebodeaux’s
registration obligations); compare post, at 10, n. 3
(THOMAS, J., dissenting) (discussing changes that did not
affect Kebodeaux). Whatever other constitutional con-
cerns might attach to such a change, as a question of
Article I power it was permissible. Just as the Federal
Government may, under the Necessary and Proper
Clause, alter the conditions of a federal prisoner’s con-
finement or adjust the timing and location of drug
tests required of a federal convict, so too could it make
                  Cite as: 570 U. S. ____ (2013)             3

              ROBERTS, C. J., concurring in judgment

slight modifications to a previously imposed registration
obligation.
   The majority says, more or less, the same thing. Ante,
at 8, 11–12. But sandwiched between its discussion of the
basis for Congress’s power and its discussion of the incon-
sequential nature of the changes is a discussion of benefits
from the registration system. Along with giving force to
military regulations, the majority notes, Congress could
also have “reasonably conclude[d] that registration re-
quirements . . . help protect the public from . . . federal sex
offenders and alleviate public safety concerns.” Ante, at 8.
   Maybe so, but those consequences of the registration
requirement are irrelevant for our purposes. Public safety
benefits are neither necessary nor sufficient to a proper
exercise of the power to regulate the military. What
matters—all that matters—is that Congress could have
rationally determined that “mak[ing] the civil registration
requirement at issue here a consequence of Kebodeaux’s
offense” would give force to the Uniform Code of Military
Justice adopted pursuant to Congress’s power to regulate
the Armed Forces. Ibid.
   Ordinarily such surplusage might not warrant a sepa-
rate writing. Here, however, I worry that incautious
readers will think they have found in the majority opinion
something they would not find in either the Constitution
or any prior decision of ours: a federal police power. The
danger of such confusion is heightened by the fact the
Solicitor General adopted something very close to the
police power argument, contending that “the federal gov-
ernment has greater ties to former federal sex offenders
than it does to other members of the general public,” and
can therefore impose restrictions on them even years after
their unconditional release simply to “serve[ ] . . . public-
protection purposes.” Brief for United States 34–35.
   I write separately to stress not only that a federal police
power is immaterial to the result in this case, but also that
4             UNITED STATES v. KEBODEAUX

             ROBERTS, C. J., concurring in judgment

such a power could not be material to the result in this
case—because it does not exist. See United States v.
Morrison, 529 U. S. 598, 618–619 (2000) (“ ‘[W]e always
have rejected readings of . . . the scope of federal power
that would permit Congress to exercise a police power’ ”
(quoting United States v. Lopez, 514 U. S. 549, 584–585
(1995) (THOMAS, J., concurring))).
   Our resistance to congressional assertions of such a
power has deep roots. From the first, we have recognized
that “the powers of the government are limited, and that
its limits are not to be transcended.” McCulloch, 4
Wheat., at 420–421. Thus, while the Necessary and
Proper Clause authorizes congressional action “incidental
to [an enumerated] power, and conducive to its beneficial
exercise,” Chief Justice Marshall was emphatic that no
“great substantive and independent power” can be “im-
plied as incidental to other powers, or used as a means of
executing them.” Id., at 418, 411; see also Gibbons v.
Ogden, 9 Wheat. 1, 195 (1824) (“The enumeration presup-
poses something not enumerated”).
   It is difficult to imagine a clearer example of such a
“great substantive and independent power” than the
power to “help protect the public . . . and alleviate pub-
lic safety concerns,” ante, at 8. I find it implausible to
suppose—and impossible to support—that the Framers in-
tended to confer such authority by implication rather than
expression. A power of that magnitude vested in the
Federal Government is not “consist[ent] with the letter
and spirit of the constitution,” McCulloch, supra, at 421,
and thus not a “proper [means] for carrying into Execu-
tion” the enumerated powers of the Federal Government,
U. S. Const., Art. I, §8, cl. 18. See United States v. Com-
stock, 560 U. S. 126, 153 (2010) (KENNEDY, J., concurring
in judgment) (“It is of fundamental importance to consider
whether essential attributes of state sovereignty are com-
promised by the assertion of federal power under the
                  Cite as: 570 U. S. ____ (2013)             5

              ROBERTS, C. J., concurring in judgment

Necessary and Proper Clause”).
  It makes no difference that the Federal Government
would be policing people previously convicted of a federal
crime—even a federal sex crime. The fact of a prior fed-
eral conviction, by itself, does not give Congress a freestand-
ing, independent, and perpetual interest in protecting the
public from the convict’s purely intrastate conduct.
  But as I have said, I do not understand the majority’s
opinion to be based on such a power. The connection to
the Military Regulation Clause on which the majority
relies, ante, at 8, is less attenuated, and the power it
produces less substantial, than would be true of a federal
police power over prior federal offenders; the power to
threaten and impose particular obligations as a result of a
violation of military law is not such a “great substantive
and independent power” that the Framers’ failure to enu-
merate it must imply its absence.
  Nevertheless, I fear that the majority’s discussion of the
public-safety benefits of the registration requirement will
be mistaken for an endorsement of the Solicitor General’s
public-safety basis for the law. I accordingly concur in the
judgment only.
                    Cite as: 570 U. S. ____ (2013)                   1

                   ALITO, J., concurring in judgment

SUPREME COURT OF THE UNITED STATES
                             _________________

                             No. 12–418
                             _________________


 UNITED STATES, PETITIONER v. ANTHONY JAMES 

                 KEBODEAUX 

 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF 

            APPEALS FOR THE FIFTH CIRCUIT

                           [June 24, 2013] 


  JUSTICE ALITO, concurring in the judgment.
  I concur in the judgment solely on the ground that the
registration requirement at issue is necessary and proper
to execute Congress’ power “[t]o make Rules for the Gov-
ernment and Regulation of the land and naval Forces.”
U. S. Const., Art. I, §8, cl. 14. Exercising this power,
Congress has enacted provisions of the Uniform Code of
Military Justice (UCMJ) that authorize members of the
military to be tried before a military tribunal, rather than
a state court, for ordinary criminal offenses, including sex
crimes, that are committed both within and outside the
boundaries of a military installation. See, e.g., UCMJ Art.
2 (persons subject to UCMJ); Art. 5 (“This chapter applies
in all places”); Art. 120 (rape by a person subject to
UCMJ); Solorio v. United States, 483 U. S. 435, 436–438
(1987) (servicemember may be court-martialed for off-base
crime without “service connection”). States usually have
concurrent jurisdiction over such crimes when they are
committed off base and sometimes possess jurisdiction
over such offenses when committed on base.1 These of-
——————
   1 See 1 F. Gilligan & F. Lederer, Court-Martial Procedure §2–40.00,

p. 2–47 (3d ed. 2006) (hereinafter Gilligan & Lederer). This depends on
the circumstances under which the Federal Government acquires the
land in question. See Morrison, State Property Tax Implications for
Military Privatized Family Housing Program, 56 Air Force L. Rev. 261,
2                 UNITED STATES v. KEBODEAUX

                    ALITO, J., concurring in judgment

fenses, however, are rarely prosecuted in both a military
and a state court, and therefore when a servicemember is
court-martialed for a sex offense over which the State had
jurisdiction, this is usually because the State has deferred
to the military.2 Where the offense in question is a sex
crime, a consequence of this handling of the case is that
the offender, if convicted, may fall through the cracks of
a state registration system. For example, if the service-
member is convicted of a sex offense in a state court, the
state court may be required by state law to provide that
information to the state registry. See, e.g., Colo. Rev. Stat.
Ann. §16–22–104(1)(a)(I) (2012). State law may also
require the state corrections department to notify both
state and local police of the offender’s release. See, e.g.,
——————
269–270 (2005). See generally Manual for Courts-Martial, United
States, Rule for Court-Martial 201(d)(3) (2012) (Rule) (discussing
situations “[w]here an act or omission is subject to trial by court-
martial and by one or more civil tribunals”); D. Schlueter, Military
Criminal Justice: Practice & Procedure §4–12(A), p. 231 (8th ed. 2012)
(hereinafter Schlueter).
   2 “Where an act or omission is subject to trial by court-martial and by

one or more civil tribunals,” “the determination which nation, state, or
agency will exercise jurisdiction is a matter for the nations, states, and
agencies concerned, and is not a right of the suspect or accused.” Rule
201(d)(3). And as the commentary to Rule 201(d) explains, “the deter-
mination which agency shall exercise jurisdiction should normally be
made through consultation or prior agreement between appropriate
military officials . . . and appropriate civilian authorities.” See Discus-
sion following Rule 201(d), p. 2–10; see also Secretary of Air Force, Air
Force Instruction 51–201, §§2.6.1–2.6.3 (June 6, 2013); Schlueter
§4-12(B), at 231–232. “[I]t is constitutionally permissible to try a person
by court-martial and by a State court for the same act,” Discussion
following Rule 201(d), at 2–10; see Schlueter §4–12(B), at 232, §13–
3(F), at 691; however, “as a matter of policy a person who is pending
trial or has been tried by a State court should not ordinarily be tried
by court-martial for the same act,” Discussion following Rule 201(d), at
2–10; Air Force Instruction 51–201, §§2.6.1, 2.6.2; Gilligan & Lederer
§7–50.00, at 7–17.
                  Cite as: 570 U. S. ____ (2013)             3

                ALITO, J., concurring in judgment

§16–22–107(3). Provisions such as these are designed to
prevent sex offenders from avoiding registration, as many
have in the past. See H. R. Rep. No. 109–218, pt. 1, p. 26
(2005) (despite pre-SORNA registration efforts, “[t]he most
significant enforcement issue in the sex offender program
[was] that over 100,000 sex offenders, or nearly one-fifth
in the Nation are ‘missing,’ meaning that they have not
complied with sex offender registration requirements”).
When a servicemember is convicted by a military tribunal,
however, the State has no authority to require that tribu-
nal to notify the state registry, nor does it have the au-
thority to require the officials at a military prison to notify
state or local police when the servicemember is released
from custody. Because the exercise of military jurisdiction
may have this effect—in other words, may create a gap in
the laws intended to maximize the registration of sex
offenders—it is necessary and proper for Congress to
require the registration of members of the military who
are convicted of a qualifying sex offense in a military
court. When Congress, in validly exercising a power ex-
pressly conferred by the Constitution, creates or exacer-
bates a dangerous situation (here, the possibility that a
convicted sex offender may escape registration), Congress
has the power to try to eliminate or at least diminish that
danger. See United States v. Comstock, 560 U. S. 126,
155–158 (2010) (ALITO, J., concurring in judgment). I
accordingly concur in the judgment only.
                  Cite as: 570 U. S. ____ (2013)            1

                      SCALIA, J., dissenting

SUPREME COURT OF THE UNITED STATES
                          _________________

                           No. 12–418
                          _________________


 UNITED STATES, PETITIONER v. ANTHONY JAMES
                 KEBODEAUX
 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
            APPEALS FOR THE FIFTH CIRCUIT
                         [June 24, 2013]

   JUSTICE SCALIA, dissenting.
   I join Parts I, II, and III–B of JUSTICE THOMAS’s dissent.
I do not join Part III–A because I do not agree that what is
necessary and proper to enforce a statute validly enacted pur-
suant to an enumerated power is not itself necessary and
proper to the execution of an enumerated power. It is my
view that if “Congress has the authority” to act, then it
also “‘possesses every power needed’” to make that action
“‘effective.’” Gonzales v. Raich, 545 U. S. 1, 36 (2005)
(SCALIA, J., concurring in judgment) (quoting United States
v. Wrightwood Dairy Co., 315 U. S. 110, 118–119 (1942)). If
I thought that SORNA’s registration requirement were “‘rea-
sonably adapted,’” Raich, supra, at 37, to carrying into
execution some other, valid enactment, I would sustain it.
   But it is not. The lynchpin of the Court’s reasoning is
that Kebodeaux was “subject to a federal registration
requirement”—the Wetterling Act—at the time of his
offense, and so the Necessary and Proper Clause “author-
ized Congress to modify the requirement as in SORNA
and to apply the modified requirement to Kebodeaux.”
Ante, at 6. That does not establish, however, that the
Wetterling Act’s registration requirement was itself a
valid exercise of any federal power, or that SORNA is
designed to carry the Wetterling Act into execution. The
former proposition is dubious, the latter obviously untrue.
                     Cite as: 570 U. S. ____ (2013)                   1

                        THOMAS, J., dissenting

SUPREME COURT OF THE UNITED STATES
                             _________________

                              No. 12–418
                             _________________


 UNITED STATES, PETITIONER v. ANTHONY JAMES
                 KEBODEAUX
 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
            APPEALS FOR THE FIFTH CIRCUIT
                            [June 24, 2013]

   JUSTICE THOMAS, with whom JUSTICE SCALIA joins as to
Parts I, II, and III–B, dissenting.
   Anthony Kebodeaux was convicted under the Sex Of-
fender Registration and Notification Act (SORNA), 42
U. S. C. §16901 et seq., for failing to update his sex of-
fender registration when he moved from one Texas city to
another. The Court today holds that Congress has power
under the Necessary and Proper Clause to enact SORNA
and criminalize Kebodeaux’s failure to update his registra-
tion. I disagree. As applied to Kebodeaux, SORNA does
not “carr[y] into Execution” any of the federal powers enu-
merated in the Constitution. Art. I, §8, cl. 18. Rather,
it usurps the general police power vested in the States.
Because SORNA’s registration requirements are unconsti-
tutional as applied to Kebodeaux, I respectfully dissent.
                             I
  Congress enacted SORNA in 2006. SORNA requires
that every “sex offender shall register, and keep the regis-
tration current, in each jurisdiction where the offender
resides, where the offender is an employee, and where the
offender is a student.” 42 U. S. C. §16913(a).1 These re-
——————
  1 A “sex offender” is defined as “an individual who was convicted” of

an offense that falls within the statute’s defined offenses. 42 U. S. C.
§§16911(1) and (5)–(7).
2              UNITED STATES v. KEBODEAUX

                    THOMAS, J., dissenting

quirements “apply to all sex offenders, including sex of-
fenders convicted of the offense for which registration is
required prior to the enactment of [SORNA].” 28 CFR
§72.3 (2012). As relevant here, SORNA makes it a federal
crime when someone who is required to register as a sex
offender “knowingly fails to register or update a regis-
tration” and that person “is a sex offender [as defined
by SORNA] by reason of a conviction under Federal
law (including the Uniform Code of Military Justice).” 18
U. S. C. §§2250(a)(2)(A), (3).
  In March 1999, Anthony Kebodeaux had consensual sex
with a 15-year-old girl when he was a 20-year-old Air-
man in the U. S. Air Force. He was convicted by a court-
martial of carnal knowledge of a female under the age
of 16, in violation of Article 120(b) of the Uniform Code of
Military Justice (UCMJ). He was sentenced to three
months’ imprisonment and received a bad-conduct dis-
charge. He completed his sentence in September 1999 and
was no longer in federal custody or the military when
Congress enacted SORNA, which required him to register
as a sex offender. In 2007, Kebodeaux failed to update his
sex-offender registration within three days of moving from
El Paso, Texas, to San Antonio, Texas. He was convicted
under §2250(a)(2)(A) in 2008 and sentenced to a year and
a day in prison. The question before the Court is whether
Congress has power to require Kebodeaux to register as a
sex offender and to criminalize his failure to do so.
                            II

                            A

  The Constitution creates a Federal Government with
limited powers. Congress has no powers except those
specified in the Constitution. See Marbury v. Madison,
1 Cranch 137, 176 (1803) (Marshall, C. J.) (“The powers of
the legislature are defined, and limited; and that those
limits may not be mistaken, or forgotten, the constitution
                 Cite as: 570 U. S. ____ (2013)           3

                    THOMAS, J., dissenting

is written”). Thus, “[e]very law enacted by Congress must
be based on one or more of its powers enumerated in the
Constitution.” United States v. Morrison, 529 U. S. 598,
607 (2000).
   A different default rule applies to the States. As the
Tenth Amendment makes clear, the States enjoy all pow-
ers that the Constitution does not withhold from them.
(“The powers not delegated to the United States by the
Constitution, nor prohibited by it to the States, are re-
served to the States respectively, or to the people”) While
the powers of Congress are “few and defined,” the powers
that “remain in the State governments are numerous and
indefinite.” The Federalist No. 45, p. 328 (B. Wright ed.
1961) (J. Madison).
   The Constitution sets forth Congress’ limited powers in
Article I. That Article begins by “vest[ing]” in Congress
“[a]ll legislative Powers herein granted,” and then enu-
merates those powers in §8. The final clause of §8, the
Necessary and Proper Clause, gives Congress power “[t]o
make all Laws which shall be necessary and proper for
carrying into Execution the foregoing Powers and all other
Powers vested by this Constitution in the Government
of the United States, or in any Department or Officer
thereof.” Art. I, §8, cl. 18. Importantly, the Necessary and
Proper Clause is not a freestanding grant of congressional
power, but rather an authorization to makes laws that are
necessary to execute both the powers vested in Congress
by the preceding clauses of §8, and the powers vested in
Congress and the other branches by other provisions of the
Constitution. See, e.g., Kinsella v. United States ex rel.
Singleton, 361 U. S. 234, 247 (1960) (“The [Necessary and
Proper Clause] is not itself a grant of power, but a caveat
that the Congress possesses all the means necessary to
carry out the specifically granted ‘foregoing’ powers of §8
‘and all other Powers vested by this Constitution’ ”).
   In McCulloch v. Maryland, 4 Wheat. 316 (1819), Chief
4               UNITED STATES v. KEBODEAUX

                      THOMAS, J., dissenting

Justice Marshall famously set forth the Court’s interpreta-
tion of the Necessary and Proper Clause:
    “Let the end be legitimate, let it be within the scope of
    the constitution, and all means which are appropriate,
    which are plainly adapted to that end, which are not
    prohibited, but consist[ent] with the letter and spirit
    of the constitution, are constitutional.” Id., at 421.
Under this formulation, a federal law is a valid exercise of
Congress’ power under the Clause if it satisfies a two-part
test. “First, the law must be directed toward a ‘legitimate’
end, which McCulloch defines as one ‘within the scope of
the [C]onstitution.’ ” United States v. Comstock, 560
U. S. 126, 160 (2010) (THOMAS, J., dissenting) (quoting 4
Wheat., at 421). In other words, the law must be directed
at “carrying into Execution” one or more of the powers
delegated to the Federal Government by the Constitution.
Art. I, §8, cl. 18. “Second, there must be a necessary and
proper fit between the ‘means’ (the federal law) and the
‘end’ (the enumerated power or powers) it is designed to
serve.” Comstock, 560 U. S., at 160 (THOMAS, J., dissent-
ing). “The means Congress selects will be deemed ‘neces-
sary’ if they are ‘appropriate’ and ‘plainly adapted’ to the
exercise of an enumerated power, and ‘proper’ if they are
not otherwise ‘prohibited’ by the Constitution and not
‘[in]consistent’ with its ‘letter and spirit.’ ” Id., at 160–161
(quoting Art. I, §8, cl. 18 and McCulloch, 4 Wheat., at
421).
   Both parts of this test are critical. “[N]o matter how
‘necessary’ or ‘proper’ an Act of Congress may be to its
objective, Congress lacks authority to legislate if the objec-
tive is anything other than ‘carrying into Execution’ one or
more of the Federal Government’s enumerated powers.”
Comstock, supra, at 161 (THOMAS, J., dissenting). As
applied to Kebodeaux, SORNA fails this test.
                  Cite as: 570 U. S. ____ (2013)            5

                     THOMAS, J., dissenting

                               B
   It is undisputed that no enumerated power in Article I,
§8, gives Congress the power to punish sex offenders who
fail to register, nor does any other provision in the Consti-
tution vest Congress or the other branches of the Federal
Government with such a power. Thus, SORNA is a valid
exercise of congressional authority only if it is “necessary
and proper for carrying into Execution” one or more of
those federal powers enumerated in the Constitution.
   In the course of this litigation, the Government has
argued that Kebodeaux’s conviction under §2250(a)(2)(A)
executes Congress’ enumerated powers to spend for the gen-
eral welfare, Art. I, §8, cl. 1; to regulate interstate com-
merce, §8, cl. 3; and to regulate the armed forces, §8,
cl. 14. But none of these powers justifies applying
§2250(a)(2)(A) to Kebodeaux. The Spending Clause ar-
gument is a nonstarter. Section 2250(a)(2)(A) does not
execute Congress’ spending power because it regulates
individuals who have not necessarily received federal funds
of any kind. The Government contends that “federal fund-
ing and logistical support offered to States for their sex-
offender-registration-and-notification programs can be
effective only if persons required to register actually do so”
and that “Congress may impose penalties on such individ-
uals as a means of achieving that goal.” Brief for United
States 52. But we have never held that Congress gains
the power to regulate private individuals merely because
it provides money to the States in which they reside.
   Nor does the Commerce Clause—the enumerated power
that the Court has construed most broadly—support
§2250(a)(2)(A). Under this Court’s precedents, Congress
may use its Commerce Clause power to regulate (1) “ ‘the
use of the channels of interstate commerce,’ ” (2) “ ‘the
instrumentalities of interstate commerce, or persons or
things in interstate commerce,’ ” and (3) economic activi-
ties that “ ‘substantially affect interstate commerce.’ ”
6              UNITED STATES v. KEBODEAUX

                     THOMAS, J., dissenting

United States v. Lopez, 514 U. S. 549, 558–559 (1995); see
also Morrison, 529 U. S., at 617. Section 2250(a)(2)(A)
does not fall within the first two categories because it is
not limited to regulating sex offenders who have traveled
in interstate commerce. Instead, it applies to all federal
sex offenders who fail to register, even if they never cross
state lines. Nor does §2250(a)(2)(A) fall within the third
category. Congress may not regulate noneconomic activity,
such as sex crimes, based on the effect it might have on
interstate commerce. Cf. Morrison, supra, at 617. (“We . . .
reject the argument that Congress may regulate noneco-
nomic, violent criminal conduct based solely on that con-
duct’s aggregate effect on interstate commerce”). In short,
§2250(a)(2)(A) regulates activity that is neither “ ‘inter-
state’ ” nor “ ‘commercial,’ ” 687 F. 3d 232, 253 (CA5 2012),
and, thus, it cannot be justified on the ground that it
executes Congress’ power to regulate interstate commerce.
  Finally, Congress’ power “[t]o make Rules for the Gov-
ernment and Regulation of the land and naval Forces”
does not support Kebodeaux’s conviction under §2250(a)
(2)(A). Art. I, §8, cl. 14. Kebodeaux had long since
fully served his criminal sentence for violating Article
120(b) of the UCMJ and was no longer in the military
when Congress enacted SORNA. Congress does not retain
a general police power over every person who has ever
served in the military. See United States ex rel. Toth v.
Quarles, 350 U. S. 11, 14 (1955) (“It has never been inti-
mated by this Court . . . that Article I military jurisdiction
could be extended to civilian ex-soldiers who had severed
all relationship with the military and its institutions. . . .
[G]iven its natural meaning, the power granted Congress
‘To make Rules’ to regulate ‘the land and naval Forces’
would seem to restrict court-martial jurisdiction to per-
sons who are actually members or part of the armed
forces”).     Accordingly, Kebodeaux’s conviction under
§2250(a)(2)(A) cannot be sustained based on Congress’
                 Cite as: 570 U. S. ____ (2013)            7

                    THOMAS, J., dissenting

power over the military.
  Moreover, it is clear from the face of SORNA and from
the Government’s arguments that it is not directed at
“carrying into Execution” any of the federal powers enu-
merated in the Constitution, Art. I, §8, cl. 18, but is in-
stead aimed at protecting society from sex offenders and
violent child predators. See 42 U. S. C. §16901 (“In order
to protect the public from sex offenders and offenders
against children, and in response to the vicious attacks by
violent predators against the victims listed below, Con-
gress in this chapter establishes a comprehensive national
system for the registration of those offenders”); Tr. of Oral
Arg. 3 (“Convicted sex offenders pose a serious threat to
public safety. When those convictions are entered under
Federal law, Congress has the authority to impose both a
criminal and a civil sanction for that conduct in order to
protect the public”); Brief for United States 3 (same).
  Protecting society from sex offenders and violent child
predators is an important and laudable endeavor. See
Kennedy v. Louisiana, 554 U. S. 407, 467 (2008) (ALITO, J.,
dissenting) (explaining that, for most Americans, sexual
abuse of children is the “epitome of moral depravity”). But
“the Constitution does not vest in Congress the authority
to protect society from every bad act that might befall it.”
Comstock, 560 U. S., at 165 (THOMAS, J., dissenting). The
power to protect society from sex offenders is part of
the general police power that the Framers reserved to the
States or the people. See Amdt. 10; Morrison, supra, at
617 (“[W]e can think of no better example of the police
power, which the [Framers] denied the National Govern-
ment and reposed in the States, than the suppression of
violent crime and vindication of its victims”); Lopez, supra,
at 561, n. 3. (“ ‘[T]he ‘States possess primary authority for
defining and enforcing the criminal law’ ” (quoting Brecht
8                 UNITED STATES v. KEBODEAUX

                        THOMAS, J., dissenting

v. Abrahamson, 507 U. S. 619, 635 (1993))).2
——————
   2 All 50 States have used their general police powers to enact sex

offender registration laws. See, e.g., Ala. Code §§13A–11–200 to 13A–
11–202, 13A–11–1181 (2006); Alaska Stat. §§11.56.840, 12.63.010 to
12.63.100, 18.66.087, 28.05.048, 33.30.035 (2006); Ariz. Rev. Stat. Ann.
§§13–3821 to 13–3825 (2001 and Supp. 2007); Ark. Code Ann. §§12–12–
901 to 12–12–909 (2003 and Supp. 2007); Cal. Penal Code Ann. §§290
to 290.4 (2008); Colo. Rev. Stat. Ann. §§16–22–103 to 16–22–104, 18–3–
412.5 (2007); Conn. Gen. Stat. §§54–251 to 54–254 (2008 Supp.); Del.
Code Ann., Tit. 11, §4120 (2007); Fla. Stat. Ann. §§775.13, 775.21
(2007); Ga. Code Ann. §42–1–12 (Supp. 2007); Haw. Rev. Stat. §§846E–
1, 846E–2 (2006 Cum. Supp.); Idaho Code §§18–8304 to 18–8311 (Supp.
2008); Ill. Comp. Stat., ch. 730, §§150/1 to 150/10, 152/101 to 152/121
(West 2006); Ind. Code §§11–8–8–1 to 11–8–8–7 (Supp. 2007); Iowa
Code §§692A.1 to 692A.16 (2003 and Supp. 2008); Kan. Stat. Ann.
§§22–4901 to 22–4910 (1995); Ky. Rev. Stat. Ann. §§17.500 to 17.540
(Lexis 2003 and Supp. 2007); La. Rev. Stat. Ann. §§15:540 to 15:549
(2005 and Supp. 2008); Me. Rev. Stat. Ann., Tit. 34–A, §§11201 to
11204, 11221 to 11228 (2007 Supp. Pamphlet); Md. Crim. Proc. Code
Ann. §§11–701 to 11–721 (Lexis 2001 and Supp. 2007); Mass. Gen.
Laws, ch. 6, §§178D to 178T (West 2006 and Supp. 2008); Mich. Comp.
Laws §§28.721 to 28.731 (West 2004 and Supp. 2008); Minn. Stat. Ann.
§243.166 (West 2003 and Supp. 2008); Miss. Code Ann. §§45–33–21 to
45–33–59 (West 1999 and Supp. 2007); Mo. Rev. Stat. §§589.400 to
589.425 (2003 and Supp. 2008), §211.45 (2004); Mont. Code Ann. §§46–
23–501 to 46–23–507 (2007); Neb. Rev. Stat. §§29–4001 to 29–4013
(2003 and Supp. 2007); Nev. Rev. Stat. §§179B.010 to 179B.250 (2007);
N. H. Rev. Stat. Ann. §§651–B:1 to 651–B:7 (West 2007 and Supp.
2007); N. J. Stat. Ann. §§2C:7–1 to 2C:7–20 (West 2005 and Supp.
2008); N. M. Stat. Ann. §§29–11A–1 to 29–11A–8 (2004 and Supp. 2008);
N. Y. Correc. Law Ann., Art. 6–C, §§168 to 168–V (West 2003 and
Supp. 2008); N. C. Gen. Stat. Ann. §§14–208.5 to 14–208.26 (Lexis
2007); N. D. Cent. Code Ann. §12.1–32–15 (Lexis 1997 and Supp. 2007);
Ohio Rev. Code Ann. §§2950.01 to 2950.11 (West 2006 and Supp. 2008);
Okla. Stat., Tit. 57, §§581 to 585 (West 2001), Tit. 57, §§591 to 594
(West 2007 Supp.); Ore. Rev. Stat. §§181.585 to 181.606, 181.826
(2007); 42 Pa. Cons. Stat. §§9791 to 9799.9 (2006); R. I. Gen. Laws
§§11–37.1–1 to 11–37.1–12 (2002 and Supp. 2007); S. C. Code Ann.
§§23–3–430 to 23–3–490 (2007 and Supp. 2007); S. D. Codified Laws
§§22–24B–1 to 22–24B–15 (2006 and Supp. 2008); Tenn. Code Ann.
§§40–39–201 to 40–39–212 (2006 and Supp. 2007); Tex. Crim. Proc.
Code Ann., Arts. 62.001 to 62.002, 62.051 to 62.059 (Vernon 2006 and
                    Cite as: 570 U. S. ____ (2013)                   9

                        THOMAS, J., dissenting

  The Government has failed to identify any enumerated
power that §2250(a)(2)(A) “carr[ies] into Execution” in this
case. Accordingly, I would hold that §2250(a)(2)(A) and
the registration requirements that it enforces are uncon-
stitutional as applied to Kebodeaux.
                             III
   In concluding otherwise, the Court entirely skips
McCulloch’s first step—determining whether the end
served by SORNA is “within the scope of the [C]onstitu-
tion.” 4 Wheat., at 421. The Court appears to believe
that Congress’ power “to ‘make Rules for the . . . Regula-
tion of the land and naval Forces’ ” justifies imposing
SORNA’s registration requirements on Kebodeaux. Ante,
at 6. But not one line of the opinion explains how SORNA
is directed at regulating the armed forces. Instead, the
Court explains how SORNA and the Wetterling Act serve
various ends that are not enumerated in the Constitution.
Cf. ante, at 12 (explaining that SORNA was designed to
“keep track of more offenders” and “encourage States . . .
to adopt its uniform standards”); ante, at 8 (explaining
that the Wetterling Act was designed to “protect the public
from . . . federal sex offenders and alleviate public safety
concerns”). The Court’s failure to link SORNA to any
enumerated power results in analysis that is untethered
from the Constitution and disregards the admonition that
“[t]he powers of the legislature are defined, and limited.”
Marbury, 1 Cranch, at 176.


—————— 

Supp. 2008); Utah Code Ann. §77–27–21.5 (2003 and 2008 Supp.); Vt. 

Stat. Ann., Tit. 13, §§5401 to 5414 (1998 and Supp. 2007); Va. Code

Ann. §§9.1–900 to 9.1–921 (2006 and Supp. 2007); Wash. Rev. Code 

§§4.24.550, 9A.44.130, 9A.44.140, 10.01.200, 70.48.470, 72.09.830

(2006); W. Va. Code Ann. §§15–12–1 to 15–12–10 (Lexis 2004 and Supp. 

2007); Wis. Stat. §§301.45 to 301.48 (2005 and Supp. 2007); Wyo. Stat. 

Ann. §§7–19–301 to 7–19–307 (2005).

10               UNITED STATES v. KEBODEAUX

                        THOMAS, J., dissenting


                              A

   The Court’s analysis is flawed at every step. It begins
by explaining that “at the time of his offense Kebodeaux
was subject to the federal Wetterling Act, an Act that
imposed upon him registration requirements very similar
to those that SORNA later mandated.”3 Ante, at 4. But
that is beside the point. Kebodeaux was convicted of
violating SORNA’s registration requirements, not the
Wetterling Act’s, and so the relevant question is what
enumerated power SORNA “carr[ies] into Execution.”
“The Necessary and Proper Clause does not provide Con-
gress with authority to enact any law simply because it
furthers other laws Congress has enacted in the exercise
of its incidental authority; the Clause plainly requires
a showing that every federal statute ‘carr[ies] into
Execution’ one or more of the Federal Government’s enu-
merated powers.” Comstock, 560 U. S., at 168 (THOMAS,
J., dissenting).
   Nevertheless, apparently in an effort to bootstrap the
Wetterling Act, the Court proceeds to determine whether
the Wetterling Act (not SORNA) falls within Congress’

——————
   3 THE CHIEF JUSTICE wrongly asserts that the differences between the

Wetterling Act and SORNA are “insignificant.” Ante, at 2 (opinion
concurring in judgment). SORNA increases the federal penalty for fail-
ing to register from a misdemeanor punishable by no more than one
year to a felony punishable by up to 10 years for a first offense. Com-
pare 18 U. S. C. §2250(a) with 42 U. S. C. §14072(i) (2000 ed.). It is
simply incorrect to minimize that change by saying that Kebodeaux
received only a day more than he could have received for failing to
register under the Wetterling Act. Ante, at 2 (ROBERTS, C. J., concur-
ring in judgment). The “legally prescribed range is the penalty affixed
to the crime,” Alleyne v. United States, ante, at 11, and SORNA in-
creased that range significantly. SORNA also requires that a sex
offender who moves update his registration within three days of mov-
ing, instead of seven. Compare 42 U. S. C. §16913(c) with App. to Pet.
for Cert. 167a–168a. Thus, a person can be convicted under SORNA for
conduct that would have complied with the Wetterling Act.
                 Cite as: 570 U. S. ____ (2013)           11

                    THOMAS, J., dissenting

power under the Necessary and Proper Clause. The Court
first notes that the Clause “ ‘leave[s] to Congress a large
discretion as to the means that may be employed in exe-
cuting a given power,’ ” ante, at 7 (quoting Lottery Case,
188 U. S. 321, 355 (1903))—a fact that is entirely irrele-
vant under McCulloch’s first step of determining whether
the end is itself legitimate. The Court then observes that
the Necessary and Proper Clause
    “authorizes Congress, in the implementation of other
    explicit powers, to create federal crimes, to confine of-
    fenders to prison, to hire guards and other prison per-
    sonnel, to provide prisoners with medical care and
    educational training, to ensure the safety of those who
    may come into contact with prisoners, to ensure the
    public’s safety through systems of parole and super-
    vised release, and, where a federal prisoner’s mental
    condition so requires, to confine that prisoner civilly
    after the expiration of his or her term of imprison-
    ment.” Ante, at 7.
From these powers, the Court reasons that the Wetterling
Act is valid because “Congress could reasonably conclude
that registration requirements applied to federal sex
offenders after their release can help protect the public
from those federal sex offenders and alleviate public safety
concerns.” Ante, at 8. As I explained in Comstock, how-
ever, this mode of analysis confuses the inquiry. 560 U. S.
at 168–169 (THOMAS, J., dissenting). “Federal laws that
criminalize conduct . . . , establish prisons for those who
engage in that conduct, and set rules for the care and
treatment of prisoners awaiting trial or serving a criminal
sentence” are only valid if they “ ‘Execut[e]’ ” an enumer-
ated power. Id., at 169. Here, for example, Congress has
authority to enact Article 120(b) of the UCMJ, to enforce
that provision against military personnel who violate it,
and to confine them in a military prison while they are
12             UNITED STATES v. KEBODEAUX

                    THOMAS, J., dissenting

awaiting trial and serving a sentence. All of those actions
“carr[y] into Execution” Congress’ power to promote order
and discipline within the military by regulating the con-
duct of military personnel. Art. I, §8, cl. 14.
    But the enumerated power that justified Kebodeaux’s
conviction does not justify requiring him to register as a
sex offender now that he is a civilian. If Kebodeaux were
required to register as part of his criminal sentence, then
registration would help execute the power that justifies
his conviction. The court-martial here, however, did not
impose registration requirements at Kebodeaux’s sentenc-
ing. See ante, at 8 (acknowledging that registration is a
“civil requirement” and was “not a specific condition of
Kebodeaux’s release”). Enacted long after Kebodeaux had
completed his sentence, SORNA cannot be justified as a
punishment for the offense Kebodeaux committed while in
the military because retroactively increasing his punish-
ment would violate the Ex Post Facto Clause. See Peugh
v. United States, 569 U. S. ___, ___ (2013) (slip op., at 8)
(explaining that laws that “ ‘inflic[t] a greater punishment
. . . than the law annexed to the crime . . . when commit-
ted’ ” violate the Ex Post Facto Clause) (quoting Calder v.
Bull, 3 Dall. 386, 390 (1798)); Peugh, supra, at ___
(THOMAS, J., dissenting) (slip op., at 11) (explaining that
“laws retroactively increasing the punishment were . . .
understood to be ex post facto at the time of the found-
ing”). As the Court below correctly recognized, “because
SORNA’s registration requirements are civil and were
enacted after Kebodeaux committed his crime, the
[G]overnment cannot justify their constitutionality on the
ground that they merely punish Kebodeaux for the crime
he committed while in the military.” 687 F. 3d, at 239.
The only justification for SORNA that the Government
has advanced is protection of the public, but that justifica-
tion has nothing to do with Congress’ power to regulate
                      Cite as: 570 U. S. ____ (2013)                    13

                         THOMAS, J., dissenting

the armed forces.4
   Finally, the Court asserts that the Wetterling Act is
reasonable because it “took state interests into account
by, for the most part, requiring released federal offenders
to register in accordance with state law,” and its require-
ments are “reasonably narrow and precise.” Ante, at 10.
But the degree to which the Wetterling Act or SORNA
accommodates State interests and intrudes on the lives of
individuals subject to registration is irrelevant because
the Supremacy Clause makes federal law supreme. See
Art. VI, cl. 2. “As long as it is acting within the powers
granted it under the Constitution, Congress may impose
its will on the States.” Gregory v. Ashcroft, 501 U. S. 452,

——————
   4 THE CHIEF JUSTICE contends that Congress has authority to impose

registration as a consequence of Kebodeaux’s conviction because “[a]
servicemember will be less likely to violate a relevant military regula-
tion if he knows that, having done so, he will be required to register as
a sex offender years into the future.” Ante, at 2. But SORNA could not
possibly have deterred Kebodeaux from violating any military regula-
tion because it was enacted after he left the military.
   JUSTICE ALITO contends that, by trying members of the military in a
military court, Congress exacerbated “the possibility that a convicted
sex offender may escape [the state] registration [system],” and that
SORNA is necessary and proper to correct this problem. Ante, at 3
(opinion concurring in judgment). But JUSTICE ALITO has not identified
any enumerated power that gives Congress authority to address this
supposed problem, and there is no evidence that such a problem exists.
Indeed, Texas has indicated that SORNA undermines its registration
system, rather than making it more effective. See Letter from Jeffrey
S. Boyd, General Counsel and Acting Chief of Staff, Texas Office of the
Governor, to Linda Baldwin, Director, SMART Office 1 (Aug. 17, 2011)
(“Although we in Texas certainly appreciate and agree with the stated
goals of SORNA, the adoption of this ‘one-size-fits-all’ federal legisla-
tion in Texas would in fact undermine the accomplishment of those
objectives in Texas, just as it would in most other states”), online
at http: // www.ncleg.net / documentsites / committees / JLOCJPS / October%
2013,%202011%20Meeting / RD_SORNA_General_Information_2011-10-
13.pdf (as visited June 21, 2013, and available in Clerk of Court’s case
file).
14             UNITED STATES v. KEBODEAUX

                     THOMAS, J., dissenting

460 (1991). The fact that the Wetterling Act and SORNA
may be “narrow” and “[take] state interests into account,”
ante, at 10, is “not a matter of constitutional necessity, but
an act of legislative grace.” Comstock, 560 U. S., at 178
(THOMAS, J., dissenting). These factors have no place in
deciding whether a law “Execut[es]” an enumerated power.
                              B
   The Court not only ignores the limitations on Congress’
power set forth in the Constitution, but it also ignores the
limits that it marked just three years ago in Comstock. In
that case, this Court held that Congress has power under
the Necessary and Proper Clause to enact 18 U. S. C.
§4248, which authorizes the Federal Government to civilly
commit “sexually dangerous persons” beyond the date it
lawfully could hold them on a charge or conviction for a
federal crime. Comstock, 560 U. S., at 142. The Court
rebuffed the assertion that it was conferring a general
police power on Congress by asserting that §4248 was
“limited to individuals already ‘in the custody of the’ Fed-
eral Government.” Id., at 148. The Solicitor General even
conceded at oral argument that “the Federal Government
would not have . . . the power to commit a person who . . .
has been released from prison and whose period of super-
vised release is also completed” because “at that point the
State police power over a person has been fully reestab-
lished.” Tr. of Oral Arg. in United States v. Comstock O. T.
2009, No. 08–1224, p. 9. The Court and the Government
today abandon even that meager restriction, which itself
lies far beyond the constitutional limits. Kebodeaux was
no longer in federal custody when Congress enacted
SORNA, yet the Court disregards the fact that, even
under Comstock, release from prison and supervised re-
lease terminates any hold the Federal Government might
otherwise have and “fully reestablishe[d]” the State’s
police power over that individual.
                 Cite as: 570 U. S. ____ (2013)           15

                    THOMAS, J., dissenting

                         *    *     *
   The Framers believed that the division of powers be-
tween the Federal Government and the States would
protect individual liberty. See New York v. United States,
505 U. S. 144, 181 (1992) (“[T]he Constitution divides
authority between federal and state governments for the
protection of individuals. State sovereignty is not just an
end in itself: ‘Rather, federalism secures to citizens the
liberties that derive from the diffusion of sovereign power’”
(quoting Coleman v. Thompson, 501 U. S. 722, 759 (1991)
(Blackmun, J., dissenting)). The decision today upsets
that careful balance. I respectfully dissent.
