The United States armed forces grew from the military of the American Revolution, with the US military becoming active in several 20th century global conflicts on Earth. Of these, the US armed forces was a major participant in World War I, World War II, and the Brush Wars in Asia. The United States and the Soviet Union also engaged in a decades-long Cold War, where each side was poised to strike and destroy the other through the use of nuclear weapons. (TOS: "Space Seed"; DS9: "Our Man Bashir", "Little Green Men"; ENT: "Storm Front")
The United States military focused on both external projection of military power and homeland defense against enemy invasion, both direct and indirect. In 1996, when the USS Voyager violated United States air space, the United States military took "great interest" in the occurrence, even though more legitimate news agencies had dismissed the incident as a hoax. (VOY: "Future's End, Part II")
Branches of the US armed forces
The United States armed forces was divided into four major branches, each in charge of a specific defense area. Specifically, the Air Force patrolled Earth's atmosphere, the Navy its oceans, and the Army was in charge of land defense. The Marine Corps was an amphibious assault force attached to the Navy.
The various branches of the US armed forces were:
US military personnel
US military rank insignia
The uniforms and ranks of the United States armed forces were represented in a variety of ways, most often as metal pin insignia or, in the case of the Navy, stripes on the uniform sleeve. The later pattern of Starfleet rank pips is based on the sleeve rank insignia of the United States Navy.
The United States armed forces also maintained a number of military awards to award heroism or meritorious accomplishment by its members.