1942
'55.
Vietnam.
Part of the cold war.
1964-1975
They feared that Vietnam would become Communist if it should gain indepedence.
The Cold War, then Vietnam.
To stop the spread of communism.
The US probably became allies with South Vietnam in 1961.
New Zealand was part of ANZUS (allied with Australia & US).
to stop communism
When Nixon ordered "military trainers" to Vietnam, the U.S. then started to become actively involved in Vietnam combat.