The United States fought 1)the Viet Cong, 2) Soldiers of the North Vietnamese Army and 4) Soldiers of Communist China. The Soldiers of the North Vietnamese army were fighting for a communist Vietnam along with the soldiers of Communist China and the Soviet Union. The Viet Cong was a guerilla rebel group from the South but who was allied with the North and supported by the North. The United States allies were South Vietnam, with the help of the French at the beginning of the war.