To understand New Zealand’s role in Vietnam, it is first helpful to understand how the war came about.
The conflict had its origins in Vietnamese nationalism before World War Two and the rise of communism after it. Vietnam had been part of the French colony of Indochina since the 19th century. From 1946, the communist-dominated Viet Minh fought the French for control of the country, eventually expelling them in May 1954; the final turning-point had been the battle at Dien Bien Phu in the mountains west of Hanoi. The country was then split into communist North Vietnam and the Western-supported South Vietnam. By 1959, a state of civil war existed between them, with invasion by the National Liberation Front (also known as the Viet Cong) supported by the North Vietnamese Government threatening the US-backed South Vietnamese Government.
In response to this threat, the US Government, led by President John F. Kennedy, sent thousands of military advisors to assist the South Vietnamese forces in the early 1960s. The US began air strikes against North Vietnam in 1964 and US Marines were deployed to protect the air bases in South Vietnam from attack. Gradually, the administration of Kennedy’s successor, President Lyndon B. Johnson, was drawn into a full military commitment to South Vietnam in 1965.
Over the next eight years, the US and its allies (including Australia and New Zealand) attempted to defeat the Viet Cong and North Vietnamese. Despite huge commitment in military equipment and manpower, the effort ultimately failed and US forces withdrew in 1973, leaving the South Vietnamese to fight on. Saigon, the capital of South Vietnam, fell in April 1975, finally ending the war which cost at least 1.3 million lives on all sides. Vietnam has remained a communist-governed state ever since.