Vietnam War

The Vietnam War was fought from 1959 to April 30, 1975. Thewar was fought between the Democratic Republic of Vietnam (North Vietnam) and the United States-supported Republic of Vietnam (South Vietnam). It concluded with the United States withdrawing under terms of the Paris Peace Accord of 1973 which preserved the division temporarily, but the North Vietnamese soon disregarded the treaty and invaded South Vietnam, which quickly fell without U.S. support, and the country was reunited in 1975. This has been described as a "total" victory on the part of the North Vietnamese.

''Note: The above describes events as they occured in OTL, and those few Harry Turtledove timelines with a point of departure after 1975. The Vietnam War is germaine to the following:''

Vietnam War in "Hindsight"
American participation in the Vietnam War was an indirect impetus for Michelle Gordian's decision to travel back in time and publish science fiction. Gordian blamed the war for a waste of economic and human resources that eventually stunted the country's intellectual growth. By the 1980s, the country's interest in scientific progress had eroded. Gordian decided that traveling back to the early 1950s and spreading ideas was the only means of combating this.

At least one of her stories, Tet Offensive, was based on the Vietnam War.

Vietnam War in The Gladiator
In one alternate, the United States withdrew from the Vietnam War in 1968, leaving South Vietnam to fall to the North. This decision, coupled with the fact that the country backed down during the Cuban Missle Crisis years before demonstrated to the world that the US was a weak position. "Popular fronts" arose in Europe which pulled their countries away from the US and towards the USSR. Communism spread, and the USSR won the Cold War.