In the Vietnam war the United States and the Republic of Vietnam (RVN) opposed the revolutionary movement known as the Viet Cong. The Viet Cong was sponsored by the Communist Democratic Republic of Vietnam (DRV). This war was the second of two wars being fought in that area. The first Indochina war was a struggle between Vietnamese nationalists and the French colonial regime aided by the U.S.. In the second war we replaced France in the struggle versus the Communists. Vietnam lasted from the mid 1950s to 1975 when the U.S. finally withdrew from the war. Vietnam begun as a war to keep the French regime intact. The other side wanted to have Ho Chi Minh lead the republic after it was liberated from the Japanese in 1945. After WWII France wanted to have their power restored and Bao Dai to be the Emperor. During this initial conflict the U.S.
was providing 80% of the cost of France's war effort. The war breaks out with the U.S. getting involved with combat troops in late 1964 after the Gulf of Tonkin incident. A Major turning point for this war is considered to be the Tet Offensive (January 31, 1968) - this was a surprise attack by the Viet Cong in which they lost (Groliers).
The United States began this war with a 'bang'. Lyndon B. Johnson was the current President of the U.S.. He authorized the CIA to use special forces to conduct covert raids on northern Vietnamese soil. U.S. Naval forces ran electronic intelligence missions in the Gulf of Tonkin. Plus U.S. aid was increased with the addition of more advisors, and more money. Bombing raids were planned and basically Lyndon B. Johnson was getting prepared for a war. On August 2, 1964 he got his chance.