3.2 The Military Departments & Services

Defending the Nation

AFH 1 opens Section 5B with the constitutional duty of the military: ensure national survival, defend lives and property, and promote vital interests at home and abroad. Senior military leaders jointly underwrite a strategy of defending the homeland and assuring allies, while dissuading, deterring, and defeating enemies.

The military departments are three, and the parenthetical contents matter:

Three departments, six services. An item offering "six military departments" or placing the Space Force under its own department is wrong.

The Key West Agreement

The Secretary of Defense and the Joint Chiefs of Staff established the general and specific functions (roles and missions) of each branch in the Key West Agreement of 1948. The latest revision was in 1958. Both dates are testable, and swapping them is a common trap.

The 1958 revision states three general functions of the U.S. Armed Forces:

1. Support and defend the U.S. Constitution against all enemies, foreign and domestic.
2. Ensure, by timely and effective military action, the security of the United States, its possessions, and areas vital to its interests.
3. Uphold and advance the national policies and interests of the United States.

The agreement also directs each service to make use of the personnel, equipment, and facilities of the other services in all cases where economy and effectiveness will be increased — the origin of the joint-efficiency logic that runs through the rest of Chapter 5.

Specific Functions by Service

United States Army

The land-based branch. Mission: "To fight and win our nation's wars by providing prompt, sustained land dominance across the full range of military operations and the spectrum of conflict in support of combatant commanders."

Specific functions — organize, train, and equip land forces for:

• Operations on land, including joint operations
• The seizure or defense of land areas, including airborne and joint amphibious operations
• The occupation of land areas

United States Navy

Mission: maintain, train, and equip combat-ready naval forces capable of winning wars, deterring aggression, and maintaining freedom of the seas. The Navy includes naval combat and service forces, naval aviation, and the Marine Corps, and is organized primarily for prompt and sustained combat at sea. AFH 1 notes it is the largest, most capable navy in the world, with the highest combined battle fleet tonnage and the world's largest aircraft carrier fleet.

Five specific functions: operations at sea including joint operations; control of vital sea areas, protection of vital sea lanes, and suppression of enemy sea commerce; support of occupation forces as required; seizure of minor enemy shore positions reducible by landing forces within the fleet organization; and naval reconnaissance, antisubmarine warfare, and protection of shipping.

United States Marine Corps

Five specific functions, the first of which is the identity item: provide marine forces with supporting components for service in the seizure or defense of advanced naval bases, and the conduct of limited land operations connected with them. The others: develop, in coordination with the Army and USAF, the phases of amphibious operations pertaining to landing-force tactics, technique, and equipment; provide detachments and organizations for service on armed vessels of the Navy; provide security detachments for protection of naval property at naval stations and bases; and provide missions and detachments for service in foreign countries as required to support national policies and interests.

United States Coast Guard

The status rule is heavily tested. The Coast Guard is a military service and a branch of the U.S. Armed Forces at all times. It is a service in the Department of Homeland Security except when operating as part of the Navy on declaration of war or when the President directs.

Major functions include enforcing federal law on, under, and over the high seas and U.S. waters; maritime air surveillance or interdiction; administering and enforcing safety-of-life-and-property regulations; developing and operating aids to maritime navigation, icebreaking facilities, and rescue facilities; operating icebreaking facilities beyond U.S. waters under international agreement; oceanographic research; and maintaining readiness to function as a specialized service in the Navy in time of war, including Maritime Defense Zone command responsibilities.

United States Air Force

The USAF includes all military aviation forces, both combat and service, not otherwise specifically assigned, and is organized, trained, and equipped primarily for prompt and sustained air offensive and defensive operations. It provides the means for coordination of air defense among all services.

Eight specific functions — organize, train, and equip air forces for:

1. Air operations including joint operations
2. Gaining and maintaining general air supremacy
3. Establishing local air superiority where and as required
4. The strategic force of the United States and strategic air reconnaissance
5. Airlift and support for airborne operations
6. Air support to land forces and naval forces, including support of occupation forces
7. Air transport for the Armed Forces, except as provided by the Navy
8. Developing weapons, tactics, technique, organization, and equipment of USAF combat and service elements

Note the deliberate contrast in items 2 and 3: air supremacy is general; air superiority is local. Reversing them is the classic distractor.

United States Space Force

The Department of the Air Force is composed of air, space, and cyberspace forces, and the USAF and Space Force together are "the nation's principal air and space forces." The DAF provides global vigilance, global reach, and global power.

The Space Force, within the Department of the Air Force, has five specific functions:

1. Provide freedom of operation for the United States in, from, and to space
2. Provide prompt and sustained space operations
3. Protect the interests of the United States in space
4. Deter aggression in, from, and to space
5. Conduct space operations

The repeated phrase "in, from, and to space" is the wording to memorize; distractors typically shorten it to "in space."