The United States Armed Forces are the military forces of the United States. The armed forces consists of six service branches: the Army, Marine Corps, Navy, Air Force, Space Force, and Coast Guard. All six armed services are among the eight uniformed services of the United States.
Each of the different military services is assigned a role and domain. The Army conducts land operations, while the Navy and Marine Corps conduct maritime operations, with the Marine Corps specializing in amphibious and maritime littoral operations in support of the Navy. The Air Force conducts air operations, while the Space Force conducts space operations. The Coast Guard is unique in that it specializes in maritime operations and is also a law enforcement agency.
From their inception during the American Revolutionary War, the U.S. Armed Forces have played a decisive role in the country's history. They helped forge a sense of national unity and identity through victories in the early-19th-century First and Second Barbary Wars. They played a critical role in the territorial evolution of the U.S., including the American Civil War. The National Security Act of 1947 created the modern U.S. military framework, establishing the National Military Establishment (later the Department of Defense or DoD) headed by the secretary of defense and creating both the U.S. Air Force and National Security Council; in 1949, an amendment to the act merged the cabinet-level departments of the Army, Navy, and Air Force into the DoD.
The president of the U.S. is the commander-in-chief of the armed forces and forms military policy with the DoD and Department of Homeland Security (DHS), both federal executive departments, altogether acting as the principal organs by which military policy is carried out.
The U.S. Armed Forces are one of the largest military forces in terms of personnel. They draw their personnel from a large pool of professional volunteers. The U.S. has used military conscription, but not since 1973.