Updated December 29, 2021
Defense Primer: President’s Constitutional Authority with
Regard to the Armed Forces
Article II, Section 2, Clause 1
empowered by the Constitution to authorize the
The President shall be Commander in Chief of the Army
confiscation of enemy property during wartime, but that
and Navy of the United States, and of the Militia of the
absent such authorization, a seizure authorized by the
several States, when called into the actual Service of the
President was void.
United States....
In the Prize Cases, the Supreme Court sustained the
Commander in Chief
blockade of southern ports instituted by President Lincoln
The Constitution makes the President Commander in Chief
in April 1861, at a time when Congress was not in session.
of the Armed Forces, but does not define exactly what
Congress had at the first opportunity ratified the President’s
powers he may exercise in that role. Nor does it explain the
actions, so that it was not necessary for the Court to
extent to which Congress, using its own constitutional
consider the constitutional basis of the President’s action in
powers, may influence how the President commands the
the absence of congressional authorization or in the face of
Armed Forces. Separation-of-powers debates arise with
any prohibition. Nevertheless, the Court approved the
some frequency regarding the exercise of military powers.
blockade five-to-four as an exercise of presidential power
alone, on the basis that a state of war was a fact and that,
Early in the nation’s history, Alexander Hamilton wrote in
the nation being under attack, the President was bound to
The Federalist, No. 69, that the Commander in Chief power
take action without waiting for Congress. The case has
is “nothing more than the supreme command and direction
frequently been cited to support claims of greater
of the military and naval forces, as first general and admiral
presidential autonomy by reason of the President’s role as
of the confederacy.” Concurring in that view in 1850, the
Commander in Chief.
Supreme Court in Fleming v. Page stated, “[The
President’s] duty and his power are purely military. As
The Supreme Court has also suggested that the President
Commander in Chief, he is authorized to direct the
has some independent authority to employ the Armed
movements of the naval and military forces placed by law
Forces, at least in the absence of contrary congressional
at his command, and to employ them in the manner he may
action. In the 1890 case of In re Neagle, the Supreme Court
deem most effectual to harass and conquer and subdue the
suggested, in dictum, that the President has the power to
enemy.”
deploy the military abroad to protect or rescue persons with
significant ties to the United States. Discussing examples of
In Little v. Barreme, Chief Justice Marshall had occasion to
the executive lawfully acting in the absence of express
recognize congressional war power and to deny the
statutory authority, Justice Miller approvingly described the
exclusivity of presidential power. There, after Congress had
Martin Koszta affair, in which an American naval ship
authorized limited hostilities with France, a U.S. vessel
intervened to prevent a lawful immigrant from being
under orders from the President had seized what its
captured by an Austrian vessel, despite the absence of clear
commander believed was a U.S. merchant ship bound from
statutory authorization.
a French port, allegedly carrying contraband material.
Congress had, however, provided by statute only for seizure
The expansion of presidential power related to war, asserted
of such vessels bound to French ports. The Court held, the
as a combination of Commander in Chief authority and the
President’s instructions exceeded the authority granted by
President’s inherent authority over the nation’s foreign
Congress and were not to be given the force of law, even in
affairs, began in earnest in the 20th century. In United States
the context of the President’s military powers and even
v. Curtiss-Wright Export Corp., the Supreme Court
though the instructions might have been valid in the
confirmed that the President enjoys greater discretion when
absence of contradictory legislation.
acting with respect to matters of foreign affairs than may be
the case when only domestic issues are involved. In that
In Bas v. Tingy, the Court looked to congressional
case, Congress, concerned with the outside arming of the
enactments rather than plenary presidential power to uphold
belligerents in the war between Paraguay and Bolivia, had
military conduct related to the limited war with France. The
authorized the President to proclaim an arms embargo if he
following year, in Talbot v. Seeman, the Court upheld as
found that such action might contribute to a peaceful
authorized by Congress a U.S. commander’s capture of a
resolution of the dispute. President Franklin Roosevelt
neutral ship, saying that “[t]he whole powers of war being,
issued the requisite finding and proclamation, and Curtiss-
by the constitution of the United States, vested in congress,
Wright and associate companies were indicted for violating
the acts of that body can alone be resorted to as our guides
the embargo. They challenged the statute, arguing that
in this inquiry.” During the War of 1812, the Court
Congress had failed adequately to elaborate standards to
recognized in Brown v. United States that Congress was
guide the President’s exercise of the power thus delegated.
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Defense Primer: President’s Constitutional Authority with Regard to the Armed Forces
Writing for the Court, Justice Sutherland concluded that the
official and founder of Kata’ib Hizballah, an organization
limitations on delegation in the domestic field were
deemed responsible for attacks against U.S. and U.S.
irrelevant where foreign affairs are involved. This outcome
partner forces in Iraq. The Trump Administration
was based on the premise that foreign relations is
subsequently submitted a report to Congress describing a
exclusively an executive function combined with the
change to existing legal and policy frameworks governing
constitutional model positing that internationally, the power
the use of armed force, which explained the
of the federal government is not one of enumerated but of
Administration’s view that
inherent powers.
Article II of the United States Constitution,
Presidents from Truman to Biden have claimed independent
empowers the President, as Commander in Chief, to
authority to commit U.S. Armed Forces to involvements
direct the use of military force to protect the Nation
abroad absent any congressional participation, other than
from an attack or threat of imminent attack and to
consultation and after-the-fact financing. In 1994, for
protect important national interests. Article II thus
example, President Clinton asserted authority to order the
authorized the President to use force against forces
participation of U.S. forces in NATO actions in Bosnia-
of Iran, a state responsible for conducting and
Herzegovina based on what his Administration viewed as
directing attacks against United States forces in the
the President’s “constitutional authority to conduct U.S.
region.
foreign relations” and role as Commander in Chief.
Additionally, President Clinton protested congressional
Under the Trump Administration’s apparent view, such use
efforts to restrict the use of military forces there and
of force does not require congressional consultation or
elsewhere as an improper and possibly unconstitutional
authorization, seemingly without consideration of the
limitation on his “command and control” of U.S. forces.
likelihood of escalation into “war in the constitutional
sense.” The report also cited the 2002 authorization for the
In March 2011, President Obama ordered U.S. military
use of military force against Iraq in support of the
forces to take action as part of an international coalition to
operation.
enforce U.N. Security Council Resolution 1973. Resolution
1973 authorized U.N. Member States to take all necessary
President Biden also ordered airstrikes against Iran-backed
measures (other than through military occupation) to
militia targets in Iraq and Syria in response to rocket attacks
protect civilians from attacks by the Libyan government
against U.S. targets in Iraq, citing his “constitutional
and to establish a no-fly zone over the country. Although
authority to conduct United States foreign relations and as
these operations had not been authorized by legislation, the
Commander in Chief and Chief Executive,” rather than any
executive submitted a report to Congress that claimed the
congressional authorizations for use of military force.
President has the “constitutional authority, as Commander
in Chief and Chief Executive and pursuant to his foreign
CRS Products
affairs powers, to direct such limited military operations
abroad.”
CRS Report R41989, Congressional Authority to Limit Military
Operations, by Jennifer K. Elsea, Michael John Garcia, and
In 2018, President Trump ordered airstrikes against three
Thomas J. Nicola.
chemical weapons facilities in Syria, where U.S. troops
CRS Report R42699, The War Powers Resolution: Concepts and
were engaged in armed conflict against the Islamic State
Practice, by Matthew C. Weed.
(ISIS). The U.S. Armed Forces also have at times engaged
CRS Report R42738, Instances of Use of United States Armed
Syrian government targets on the justification of defending
Forces Abroad, 1798-2021, by Barbara Salazar Torreon and
partner forces, although the extant authorizations for the use
Sofia Plagakis.
of military force against terrorist groups responsible for the
CRS Legal Sidebar LSB10230, U.S. Strike on Syrian Airbase: Legal
attacks of September 11, 2001, and against Iraq in 2002,
under International Law?, by Jennifer K. Elsea.
arguably do not go so far as to permit extension of the
conflict to the Syrian government. The Office of Legal
CRS Legal Sidebar LSB10391, UPDATED: Recent U.S. Airstrikes:
Counsel advised the White House that attacks on Syrian
Legal Authorities and Questions, by Stephen P. Mul igan and
government targets are within the President’s Commander
Jennifer K. Elsea.
in Chief powers without need for congressional approval
CRS Report RL31693, U.S. Armed Forces Abroad: Selected
because the President “had reasonably determined that the
Congressional Votes Since 1982, by Barbara Salazar Torreon and
use of force would be in the national interest and that the
Carla Y. Davis-Castro.
anticipated hostilities would not rise to the level of a war in
the constitutional sense.”

In January 2020, President Trump ordered a strike against
Jennifer K. Elsea, Legislative Attorney
an Iranian target in Iraq, killing Qasem Soleimani, the head
of the Islamic Revolutionary Guard Corps-Quds Force
IF10534
(IRGC-QF), and Abu Mahdi al Muhandis, an Iraqi security


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Defense Primer: President’s Constitutional Authority with Regard to the Armed Forces


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https://crsreports.congress.gov | IF10534 · VERSION 9 · UPDATED

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