Updated January 15, 2021
Defense Primer: Commanding U.S. Military Operations
Military operations, both in peacetime and in war, are an
The Chain of Command
inherently complex undertaking. One key to success,
Title 10 U.S.C. §162 specifies that the chain of command
therefore, is a clear, unified chain of command. This
for military operations goes from the President, to the
enables senior leaders in the U.S. government—in
Secretary of Defense, to Commanders of Combatant
particular, the President and the Secretary of Defense—to
Commands. The Chairman of the Joint Chiefs of Staff acts
command and control military forces around the world.
as an intermediary, transmitting orders between the
Secretary of Defense and the Commanders of Combatant
A (Very) Brief History of the Chain of Command
Commands. Each Combatant Commander is a four-star
The way that the United States commands and controls its
Flag or General Officer, whose appointment is confirmed
forces is in large part a product of an inherent tension
by the Senate.
between improving the effectiveness of U.S. forces, on the
one hand, and preserving civilian control of the military, on
Unified Command Plan (UCP)
the other. The experience of World War II convinced
The UCP is a classified executive branch document that
President Truman, among others, that a greater degree of
articulates how DOD assigns responsibility for different
coordination and integration between the U.S. military
missions and areas of the world. It is prepared by the
services was necessary to improve the conduct of military
Chairman of the Joint Chiefs of Staff every two years and
operations. Yet there was concern at the time that
approved by the President. Each UCP sets forth basic
integrating these institutions might result in an overly
guidance to all unified combatant commanders; establishes
powerful military staff element that could threaten the
their missions, responsibilities, and force structure;
principle of civilian control of U.S. forces.
delineates the general geographical area of responsibility
for geographic combatant commanders; and specifies
The resulting compromise was to create a Joint Chiefs of
functional responsibilities for functional combatant
Staff, comprising all the military service chiefs, and headed
commanders. Congress is not included in this review
by a Chairman, serving as an advisory body only. As a
process but does have visibility into issues affecting UCP
corporate body, it was specifically not designed to exercise
development. It is through the UCP that the Department of
command; the Chairman of the Joint Chiefs of Staff (CJCS)
Defense develops its global map of areas of responsibilities
had no command authority. The Joint Chiefs of Staff did,
for its Combatant Commanders, reflected below.
however, have responsibility for establishing “unified
combatant commands,” which were charged with executing
Figure 1. Combatant Commanders’ Area of
military operations in different parts of the world and
Responsibility
combining the capabilities of two or more military services.
Different service chiefs were assigned executive and
administrative responsibilities for these combatant
commands, which gave them a de facto mechanism through
which they could influence ongoing military operations.
By 1953, the authority to establish Combatant Commands
(COCOMs) was assigned to the Secretary of Defense,
although the relative ambiguity of the chain of command
remained a feature of DOD operations until 1986.
Perceived shortcomings in the U.S. chain of command led
to demonstrable failures during several incidents in the late
1970s and early 1980s. The military services, in the view of
many observers, failed to effectively plan or conduct
operations jointly due to confusion over whether the
military services or unified combatant commanders were
Source: U.S. Department of Defense. Of note, USPACOM is now
ultimately in charge of operations. These incidents include
referred to as USINDOPACOM.
the operation in Grenada; the Iranian hostage rescue attempt
(often referred to as “Desert One”); and the bombing of the
The Combatant Commands Today
Marine Barracks in Beirut, Lebanon. In 1986, Congress
A COCOM is a military command with broad continuing
passed the Goldwater-Nichols Defense Reform Act (P.L.
missions under a single commander and composed of
99-433), which mandated clarifications to the chain of
significant assigned components of two or more military
command. The current command and control architecture
departments. There are currently eleven Combatant
for DOD is a product of these congressionally mandated
Commands. The COCOMs, and by extension their
changes.
commanders, have responsibility for the military’s
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Defense Primer: Commanding U.S. Military Operations
operations in their respective area of responsibility during
different components of DOD. It is located at Scott Air
both peacetime and war.
Force Base, IL.
There are seven regionally focused COCOMS, which
U.S. Cyber Command (USCYBERCOM) directs,
operate in clearly delineated areas of operation and have a
synchronizes, and coordinates cyberspace planning and
distinctive regional military focus:
operations to defend and advance national interests in
collaboration with domestic and international partners.
U.S. Africa Command (USAFRICOM), responsible for
sub-Saharan Africa. It is located at Kelley Barracks,
Service Component Commands
Stuttgart, Germany.
Service Component Commands consist of organizations,
individuals, units, detachments, and/or support forces that
U.S. European Command (USEUCOM), responsible for
belong to a particular military service but are assigned to a
all of Europe, large portions of Central Asia, parts of the
Combatant Commander. As an example, U.S. Army Europe
Middle East, and the Arctic and Atlantic Oceans. It is
(USAREUR) and U.S. Naval Forces, Europe
located at Patch Barracks, Stuttgart, Germany.
(USNAVEUR) are both service component commands to
U.S. European Command (USEUCOM). These components
U.S. Central Command (USCENTCOM), responsible
are subordinate to the Combatant Commander of the
for most of the Middle East, parts of Northern Africa
geographic theater in which they operate.
and west Asia, and part of the Indian Ocean. It is located
at MacDill Air Force Base, FL.
The Laws Governing COCOMs
COCOMs are governed by the provisions contained in
U.S. Northern Command (USNORTHCOM),
Sections 161 through 168 of Title10, Armed Forces, U.S.
responsible for the defense of the continental United
Code. These sections address the following provisions:
States and coordination of security and military
relationships with Canada and Mexico. It is located at
Section 161: The establishment of COCOMs;
Peterson Air Force Base, CO.
Section 162: Chain of command and assignment of
U.S. Southern Command (USSOUTHCOM),
forces for COCOMs;
responsible for Central America, South America, and
the Caribbean. It is located in Miami, FL.
Section 163: Role of the CJCS;
U.S. Indo-Pacific Command (USINDOPACOM),
Section 164: Assignment and powers and duties of
responsible for the Pacific Ocean, Southwest Asia,
commanders of COCOMs;
Australia, south Asia, and part of the Indian Ocean. It
shares responsibility for Alaska with U.S. Northern
Section 165: Administration and support of COCOMs;
Command. It is located at Camp H.M. Smith, HI.
Section 166: COCOM budget proposals;
U.S. Space Command (USSPACECOM), which deters
aggression and conflict, defends U.S. and allied freedom
Section 166a: Funding COCOMs through the CJCS;
of action, delivers space combat power for the
Joint/Combined force, and develops joint warfighters to
Section 166b: Funding for combating terrorism
advance U.S. and allied interests in, from, and through
readiness initiatives;
the space domain.
Section 167: Unified COCOMs for special operations
There are also four “functional” COCOMs, which operate
forces;
worldwide across geographic boundaries and provide
unique capabilities to geographic combatant commands and
Section 167a: Unified COCOMs for joint warfighting
the services:
experimentation: acquisition authority; and
U.S. Strategic Command (USSTRATCOM), responsible Section 168: Military-to-military and comparable
for controlling space, deterring attacks on the United
activities.
States and its allies, launching and operating satellite
systems, and directing the use of U.S. strategic forces. It
CRS Products
is located at Offutt Air Force Base, NE.
CRS Report R44474, Goldwater-Nichols at 30: Defense Reform
U.S. Special Operations Command (USSOCOM), which
and Issues for Congress, by Kathleen J. McInnis
provides special forces, counter-paramilitary, counter-
narcotics, guerilla, psychological warfare, civil
education, and insurgency capabilities. It is located at
MacDill Air Force Base, FL.
Kathleen J. McInnis, Analyst in International Security
U.S. Transportation Command (USTRANSCOM),
IF10542
which provides air, land and sea transportation to
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Defense Primer: Commanding U.S. Military Operations
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