The involvement of the United States in the Vietnam War began in the 1950s and greatly escalated in 1965 until its withdrawal in 1973. The U.S. military presence in Vietnam peaked in April 1969, with 543,000 military personnel stationed in the country. By the end of the U.S. involvement, more than 3.1 million Americans had been stationed in Vietnam, and 58,279 had been killed.
After World War II ended in 1945, President Harry S. Truman declared his doctrine of "containment" of communism in 1947 at the start of the Cold War. U.S. involvement in Vietnam began in 1950, with Truman sending military advisors to assist the French Union against Viet Minh rebels in the First Indochina War. The French withdrew in 1954, leaving North Vietnam in control of the country's northern half.