The South fell in 1975; the United States' search for a way out had already formed part of wider diplomacy with China and the USSR.
After the 1973 agreement, the South still depended heavily on American support and faced a determined northern opponent. Fighting continued and northern forces rebuilt their strength, while American political willingness to resume major combat had diminished. The South therefore faced continued military pressure without a return to the earlier scale of American fighting. In 1975 a northern offensive led to the collapse of the South; Saigon, the southern capital, fell on 30 April. The victory brought Vietnam under communist control, with formal state reunification following in 1976. The war left immense destruction, deaths and displacement.
Detente means an easing of tensions, not the end of all rivalry. It developed before the fall of Saigon: Nixon visited China and the Soviet Union in 1972, and the USA and USSR reached arms-control agreements limiting some weapons. American leaders hoped improved relations with Hanoi's supporters would assist a Vietnam settlement, but China and the USSR continued aiding the North. Vietnam therefore illustrates cooperation and conflict happening together. It is inaccurate to say that detente first began because the war ended in 1975.
Worked example: Put diplomacy and war on the same timeline
Does a 1972 summit prove that the Vietnam War had already ended?
- The summit indicates an attempt to improve relations on selected issues.
- At the same time, the Vietnamese war and external assistance continued.
- Explain the coexistence: powers could limit some risks while competing through local allies elsewhere.
Watch out for this
Detente began after Saigon fell in 1975.
Major diplomatic moves and arms-control agreements occurred earlier, including in 1972. The processes overlapped.
Check your understanding
What does Vietnam show about the limits of detente?
- The 1972 meetings caused China and the USSR to abandon the North's war effort.
- The USA improved relations with China and the USSR in 1972 while the war and their support for Hanoi continued.
- The 1973 agreement resolved the political division, leaving only an administrative change in 1975.