Australia joined the Vietnam war for many reasons. The major reason was Robert Menzies, the Prime Minister at the time, fear of communism and that the "domino theory" would come into effect (communism would keep heading south towards Australia) He tried to combat this through containment and forward defense. Another reason Australia joined the Vietnam war was Australia also joined the Vietnam to honour its treaties and show its support to the US as the US had helped Australia in WWII.
After the Cold War, Menzies was very afraid of communism. …