Regimental combat team

A regimental combat team was a provisional major infantry unit of the United States Army during World War II and the Korean War, and of the U.S. Marine Corps to the present day. The regimental combat team, or "R.C.T.", is formed by augmenting a regular infantry regiment with smaller tank, artillery, combat engineer, mechanized, cavalry, reconnaissance, Signal Corps, air defense, quartermaster, military police, medical, and other support units to enable it to be a self-supporting organization in the combat field.

World War II
World War II RCTs were generally of two types:
 * 1) temporary organizations configured for the accomplishment of a specific mission or series of missions,
 * 2) semi-permanent organizations designed to be deployed as a unit throughout a combat theater of operations.

Examples of the latter have been the 442nd Regimental Combat Team, 158th Infantry Regimental Combat Team and the 517th Parachute Regimental Combat Team.

Regimental combat teams combined the high cohesion of traditional regimental organization with the flexibility of tailored reinforcements to accomplish any given mission.

U.S. Army
Believing that future battlefields would be dominated by tactical nuclear weapons, the U.S. Army broke up its infantry regiments in the mid-1950s and then formed Battle Groups, four or five of which composed a pentomic infantry division. Although the pentomic structure was deemed to be a failure, reorganizations during the 1960s (ROAD) replaced the infantry regimental combat teams with brigade combat teams that were modeled after the World War II combat commands employed by American armored divisions. As a consequence, infantry battalions that were formerly grouped into regiments were scattered among the new brigades with a consequent loss of unit cohesiveness, and the unnecessary complication of unit traditions that related both to the old parent regiments and to the new brigades.

U.S. Marine Corps
The U.S. Marine Corps, has retained the regiment as a basic unit smaller than a division but larger than a battalion, and it continues to employ reinforced regiments as R.C.T.s in Iraq and Afghanistan.