Vietnam War: After a trip to Vietnam at the request of U.S. President John F. Kennedy, U.S. Senate Majority Leader Mike Mansfield becomes the first American official to comment adversely on the war's progress.

The Vietnam War was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam and South Vietnam and their allies. North Vietnam was supported by the Soviet Union and China, while South Vietnam was supported by the United States and other anti-communist nations. The conflict was the second of the Indochina wars and a proxy war of the Cold War between the Soviet Union and US. The Vietnam War was one of the postcolonial wars of national liberation, a theater in the Cold War, and a civil war, with civil warfare a defining feature from the outset. Direct US military involvement escalated from 1965 until its withdrawal in 1973. The fighting spilled into the Laotian and Cambodian Civil Wars, which ended with all three countries becoming communist in 1975.

Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about 331,000 square kilometres (128,000 sq mi) and a population of over 100 million, making it the world's fifteenth-most populous country. One of two communist states in Southeast Asia, Vietnam shares land borders with China to the north, and Laos and Cambodia to the west. Its capital is Hanoi and its largest city is Ho Chi Minh City.

John Fitzgerald Kennedy, also known as JFK, was the 35th president of the United States, serving from 1961 until his assassination in 1963. He was the first Roman Catholic and youngest person elected president at 43 years. Kennedy served at the height of the Cold War, and the majority of his foreign policy concerned relations with the Soviet Union and Cuba. A member of the Democratic Party, Kennedy represented Massachusetts in both houses of the United States Congress prior to his presidency.

The positions of majority leader and minority leader are held by two United States senators and people of the party leadership of the United States Senate. They serve as chief spokespersons for their respective political parties, holding the majority and the minority in the chamber. They are each elected to their posts by the senators of their party caucuses: the Senate Democratic Caucus and the Senate Republican Conference.