Harry S. Truman:
- Mutual Defense Assistance Act of 1949: provided aid to French forces in Vietnam, Laos, and Cambodia
Dwight D. Eisenhower:
- South Asia Treaty Organization: made to stop any communist influence in Southeast Asia
- Initiated the building of a new South Vietnam nation
John F. Kennedy
- December 1961 White Papers: investigation of the conditions in South Vietnam
- Sent advisers and machinery to South Vietnam, but not troops
Lyndon B. Johnson:
- Tonkin Gulf Resolution: it was not a declaration of war, but it granted broad military powers in Vietnam after two U.S. ships were attacked in the Gulf of Tonkin
- Operation Rolling Thunder: series of air strikes in North Vietnam
- First president to send combat troops to South Vietnam
- Richard Nixon:
- War Powers Act: stipulated that a president must inform Congress within 48 hours of sending forces into a hostile area without a declaration of war; troops must remain there no longer than 90 days unless Congress approves the president's actions
- "Vietnamization" : trained South Vietnam troops to fight while slowly pulling out American troops from the war
- Paris Peace Accords: ended the Vietnam War for the American troops