                 Cite as: 587 U. S. ____ (2019)            1

                    Statement of BREYER, J.

SUPREME COURT OF THE UNITED STATES
   MOATH HAMZA AHMED AL-ALWI v. DONALD J.
          TRUMP, PRESIDENT OF THE
            UNITED STATES, ET AL.
   ON PETITION FOR WRIT OF CERTIORARI TO THE UNITED
     STATES COURT OF APPEALS FOR THE DISTRICT OF
                   COLUMBIA CIRCUIT
               No. 18–740   Decided June 10, 2019

   The petition for a writ of certiorari is denied. JUSTICE
KAVANAUGH took no part in the consideration or decision
of this petition.
Statement of JUSTICE BREYER respecting the denial of
certiorari.
   In the immediate aftermath of the terrorist attacks of
September 11, 2001, Congress passed the Authorization
for Use of Military Force (AUMF), 115 Stat. 224. The
AUMF states that the President may “use all necessary
and appropriate force against those nations, organizations,
or persons he determines planned, authorized, committed,
or aided” those attacks.       §2(a), ibid.    In Hamdi v.
Rumsfeld, 542 U. S. 507 (2004), a majority of this Court
understood the AUMF to permit the President to detain
certain enemy combatants for the duration of the relevant
conflict. Id., at 517–518 (plurality opinion); id., at 587
(THOMAS, J., dissenting).
   Justice O’Connor’s plurality opinion cautioned that “[i]f
the practical circumstances” of that conflict became “en-
tirely unlike those of the conflicts that informed the devel-
opment of the law of war,” the Court’s “understanding” of
what the AUMF authorized “may unravel.” Id., at 521.
Indeed, in light of the “unconventional nature” of the “war
on terror,” there was a “substantial prospect” that deten-
tion for the “duration of the relevant conflict” could
2                    AL-ALWI v. TRUMP

                    Statement of BREYER, J.

amount to “perpetual detention.” Id., at 519–521. But as
this was “not the situation we face[d] as of th[at] date,” the
plurality reserved the question whether the AUMF or the
Constitution would permit such a result. Id., at 517–518.
  In my judgment, it is past time to confront the difficult
question left open by Hamdi. See Boumediene v. Bush,
553 U. S. 723, 797–798 (2008) (“Because our Nation’s past
military conflicts have been of limited duration, it has
been possible to leave the outer boundaries of war powers
undefined. If, as some fear, terrorism continues to pose
dangerous threats to us for years to come, the Court might
not have this luxury”); Hussain v. Obama, 572 U. S. 1079
(2014) (statement of BREYER, J., respecting denial of
certiorari).
  Some 17 years have elapsed since petitioner Moath
Hamza Ahmed al-Alwi, a Yemeni national, was first held
at the United States Naval Base at Guantanamo Bay,
Cuba. In the decision below, the District of Columbia
Circuit agreed with the Government that it may continue
to detain him so long as “armed hostilities between United
States forces and [the Taliban and al-Qaeda] persist.” 901
F. 3d 294, 298–299 (2018). The Government represents
that such hostilities are ongoing, but does not state that
any end is in sight. Brief in Opposition 4–5. As a conse-
quence, al-Alwi faces the real prospect that he will spend
the rest of his life in detention based on his status as an
enemy combatant a generation ago, even though today’s
conflict may differ substantially from the one Congress
anticipated when it passed the AUMF, as well as those
“conflicts that informed the development of the law of
war.” Hamdi, 542 U. S., at 521 (plurality opinion).
  “The denial of a writ of certiorari imports no expression of
opinion upon the merits of the case.” United States v.
Carver, 260 U. S. 482, 490 (1923). I would, in an appropri-
ate case, grant certiorari to address whether, in light of the
duration and other aspects of the relevant conflict, Con-
                Cite as: 587 U. S. ____ (2019)          3

                   Statement of BREYER, J.

gress has authorized and the Constitution permits contin-
ued detention.
