Updated December 16, 2020
Defense Primer: President’s Constitutional Authority with
Regard to the Armed Forces
Article II, Section 2, Clause 1
empowered to authorize the confiscation of enemy property
The President shall be Commander in Chief of the Army
during wartime, but that absent such authorization, a seizure
and Navy of the United States, and of the Militia of the
authorized by the President was void.
several States, when called into the actual Service of the
United States....
In the Prize Cases, the Supreme Court sustained the
blockade of southern ports instituted by President Lincoln
Commander in Chief
in April 1861, at a time when Congress was not in session.
The Constitution makes the President Commander in Chief
Congress had at the first opportunity ratified the President’s
of the Armed Forces, but does not define exactly what
actions, so that it was not necessary for the Court to
powers he may exercise in that role. Nor does it explain the
consider the constitutional basis of the President’s action in
extent to which Congress, using its own constitutional
the absence of congressional authorization or in the face of
powers, may influence how the President commands the
any prohibition. Nevertheless, the Court approved the
Armed Forces. Separation-of-powers debates arise with
blockade five-to-four as an exercise of presidential power
some frequency regarding the exercise of military powers.
alone, on the basis that a state of war was a fact and that,
the nation being under attack, the President was bound to
Early in the nation’s history, Alexander Hamilton wrote in
take action without waiting for Congress. The case has
The Federalist, No. 69, that the Commander in Chief power
frequently been cited to support claims of greater
is “nothing more than the supreme command and direction
presidential autonomy by reason of his role as Commander
of the military and naval forces, as first general and admiral
in Chief.
of the confederacy.” Concurring in that view in 1850, the
Supreme Court in Fleming v. Page stated, “[The
The Supreme Court has also suggested that the President
President’s] duty and his power are purely military. As
has some independent authority to employ the Armed
Commander in Chief, he is authorized to direct the
Forces, at least in the absence of contrary congressional
movements of the naval and military forces placed by law
action. In the 1890 case of In re Neagle, the Supreme Court
at his command, and to employ them in the manner he may
suggested, in dictum, that the President has the power to
deem most effectual to harass and conquer and subdue the
deploy the military abroad to protect or rescue persons with
enemy.”
significant ties to the United States. Discussing examples of
the executive lawfully acting in the absence of express
In Little v. Barreme, Chief Justice Marshall had occasion to
statutory authority, Justice Miller approvingly described the
recognize congressional war power and to deny the
Martin Koszta affair, in which an American naval ship
exclusivity of presidential power. There, after Congress had
intervened to prevent a lawful immigrant from being
authorized limited hostilities with France, a U.S. vessel
captured by an Austrian vessel, despite the absence of clear
under orders from the President had seized what its
statutory authorization.
commander believed was a U.S. merchant ship bound from
a French port, allegedly carrying contraband material.
The expansion of presidential power related to war, asserted
Congress had, however, provided by statute only for seizure
as a combination of Commander in Chief authority and the
of such vessels bound to French ports. The Court held, the
President’s inherent authority over the nation’s foreign
President’s instructions exceeded the authority granted by
affairs, began in earnest in the 20th century. In United States
Congress and were not to be given the force of law, even in
v. Curtiss-Wright Export Corp., the Supreme Court
the context of the President’s military powers and even
confirmed that the President enjoys greater discretion when
though the instructions might have been valid in the
acting with respect to matters of foreign affairs than may be
absence of contradictory legislation.
the case when only domestic issues are involved. In that
case, Congress, concerned with the outside arming of the
In Bas v. Tingy, the Court looked to congressional
belligerents in the war between Paraguay and Bolivia, had
enactments rather than plenary presidential power to uphold
authorized the President to proclaim an arms embargo if he
military conduct related to the limited war with France. The
found that such action might contribute to a peaceful
following year, in Talbot v. Seeman, the Court upheld as
resolution of the dispute. President Franklin Roosevelt
authorized by Congress a U.S. commander’s capture of a
issued the requisite finding and proclamation, and Curtiss-
neutral ship, saying that “[t]he whole powers of war being,
Wright and associate companies were indicted for violating
by the constitution of the United States, vested in congress,
the embargo. They challenged the statute, arguing that
the acts of that body can alone be resorted to as our guides
Congress had failed adequately to elaborate s tandards to
in this inquiry.” During the War of 1812, the Court
guide the President’s exercise of the power thus delegated.
recognized in Brown v. United States that Congress was
Writing for the Court, Justice Sutherland concluded that the
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Defense Primer: President’s Constitutional Authority w ith Regard to the Armed Forces
limitations on delegation in the domestic field were
In January 2020, President Trump ordered a strike against
irrelevant where foreign affairs are involved. This outcome
an Iranian target in Iraq, killing Qasem Soleimani, the head
was based on the premise that foreign relations is
of the Islamic Revolutionary Guard Corps -Quds Force
exclusively an executive function combined with the
(IRGC-QF), and Abu Mahdi al Muhandis, an Iraqi security
constitutional model positing that internationally, the power
official and founder of Kata’ib Hizballah, an organization
of the federal government is not one of enumerated but of
deemed responsible for attacks against U.S. and U.S.
inherent powers.
partner forces in Iraq. The Trump Administration
subsequently submitted a report to Congress describing a
Presidents from Truman to Trump have claimed
change to existing legal and policy frameworks governing
independent authority to commit U.S. Armed Forces to
the use of armed force, which explained the
involvements abroad absent any congressional
Administration’s view that
participation, other than consultation and after-the-fact
financing. In 1994, for example, President Clinton asserted
Article II of the United States Constitution,
authority to order the participation of U.S. forces in NATO
empowers the President, as Commander in Chief, to
actions in Bosnia-Herzegovina based on what his
direct the use of military force to protect the Nation
Administration viewed as the President’s “constitutional
from an attack or threat of imminent attack and to
authority to conduct U.S. foreign relations” and role as
protect important national interests. Article II thus
Commander in Chief. Additionally, President Clinton
authorized the President to use force against forces
protested congressional efforts to restrict the use of military
of Iran, a state responsible for conducting and
forces there and elsewhere as an improper and possibly
directing attacks against United States forces in the
unconstitutional limitation on his “command and control”
region.
of U.S. forces.
Under the Trump Administration’s apparent view, such use
In March 2011, President Obama ordered U.S. military
of force does not require congressional consultation or
forces to take action as part of an international coalition to
authorization, seemingly without consideration of the
enforce U.N. Security Council Resolution 1973. Resolution
likelihood of escalation into “war in the constitutional
1973 authorized U.N. Member States to take all necessary
sense.” The report also cited the 2002 authorization for the
measures (other than through military occupation) to
use of military force against Iraq in support of the
protect civilians from attacks by the Libyan government
operation.
and to establish a no-fly zone over the country. Although
these operations had not been authorized by legislation, the
CRS Products
executive submitted a report to Congress that claimed the
President has the “constitutional authority, as Commander
CRS Report R41989, Congressional Authority to Limit Military
in Chief and Chief Executive and pursuant to his foreign
Operations, by Jennifer K. Elsea, Michael John Garcia, and
affairs powers, to direct such limited military operations
Thomas J. Nicola.
abroad.”
CRS Report R42699, The War Powers Resolution: Concepts and
Practice, by Matthew C. Weed.
In 2018, President Trump ordered airstrikes against three
CRS Report R42738, Instances of Use of United States Armed
chemical weapons facilities in Syria, where U.S. troops
Forces Abroad, 1798-2020, by Barbara Salazar Torreon and
were engaged in armed conflict against the Islamic State
Sofia Plagakis.
(ISIS). The U.S. Armed Forces also have at times engaged
Syrian government targets on the justification of defending
CRS Legal Sidebar LSB10230, U.S. Strike on Syrian Airbase: Legal
partner forces, although the extant authorizations for the use
under International Law?, by Jennifer K. Elsea.
of military force against terrorist groups responsible for the
CRS Legal Sidebar LSB10391, UPDATED: Recent U.S. Airstrikes:
attacks of September 11, 2001, and against Iraq in 2002,
Legal Authorities and Questions, by Stephen P. Mul igan and
arguably do not go so far as to permit extension of the
Jennifer K. Elsea.
conflict to the Syrian government. The Office of Legal
CRS Report RL31693, U.S. Armed Forces Abroad: Selected
Counsel advised the White House that attacks on Syrian
Congressional Votes Since 1982, by Barbara Salazar Torreon and
government targets are within the President’s Commander
Carla Y. Davis-Castro.
in Chief powers without need for congressional approval
because the President “had reasonably determined that the

use of force would be in the national interest and that the
anticipated hostilities would not rise to the level of a war in
Jennifer K. Elsea, Legislative Attorney
the constitutional sense.”
IF10534


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


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https://crsreports.congress.gov | IF10534 · VERSION 8 · UPDATED

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