The most important reason why the USA withdrew from Vietnam was the Tet Offensive. How far do you agree?
Tet was very important but there were other reasons as well.
Tet was certainly a pivotal moment in changing American attitudes towards the Vietnam war. In February 1968 the communists launched a major offensive in the cities. After several weeks of brutal fighting the Americans And South Vietnamese Army regained control.
Militarily it was a defeat for the communists. However politically and psychologically it was a victory for the communists. Vietnam was the first and possibly last war fought on television. In marked contrast to what they were being told, namely an imminent US victory, the American public were sitting down each night to watch the reality of a brutal war.
What they saw for example, the seizure of the American embassy in Saigon, the execution of a Vietcong suspect and the destruction of much of the ancient city of Hue suggested the Americans were not winning and in the process were killing many innocent civilians.
Whether Tet was the most important reason for America's withdrawal was open to conjecture. By 1968 American public opinion was already turning against the war, a war which was supposed to be over very quickly but which had dragged on for several years and showed no sign of ending despite 500,000 American ground troops and a huge military budget.
One can argue that Tet was an ongoing process where psychologically American public support for the war was rapidly eroding. The revelation of the My Lai massacre is another example.
However Tet was certainly pivotal on this ongoing process.