The Vietnam War was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975.^[209] It was the second of the Indochina Wars and was officially fought between North Vietnam and South Vietnam. The north was supported by the Soviet Union, China, and other communist states, while the south was supported by the United States and other anti-communist allies.^[210] It lasted almost 20 years, with direct U.S. involvement ending in 1973. The conflict also spilled over into neighboring states, exacerbating the Laotian Civil War and the Cambodian Civil War, which ended with all three countries officially becoming communist states by 1976.^[211] Two years after the withdrawal of the last U.S. forces in 1973, Saigon, the capital of South Vietnam, fell to the communists, and the South Vietnamese army surrendered in 1975. In 1976, the government of united Vietnam renamed Saigon as Hồ Chí Minh City in honor of Hồ, who died in 1969.

The war exacted an enormous human cost and left Vietnam devastated, with the total death toll standing at between 966,000 and 3.8 million,^[212] and many thousands more crippled by weapons and substances such as napalm and Agent Orange. The U.S. Air Force destroyed more than 20% of the jungles of South Vietnam and 20–50% of the mangrove forests by spraying over 20 million gallons of toxic herbicides (defoliants) including Agent Orange.^[213] The government of Vietnam says that 4 million of its citizens were exposed to Agent Orange, and as many as 3 million have suffered illnesses because of it; these figures include the children of people who were exposed.^[214] The Red Cross of Vietnam estimates that up to 1 million people are disabled or have health problems due to contaminated Agent Orange.^[215] The end of the Vietnam War would precipitate the Vietnamese boat people and the larger Indochina refugee crisis, which saw millions of refugees leave Indochina, an estimated 250,000 of whom perished at sea.