Australian society had long harbored a fear of the "yellow hordes" waiting to "descend upon Australia" and steal it away from the privileged few white colonialists living here.
When Menzies made his statement suggesting, "The takeover of South Vietnam would be a direct military threat to Australia," the anti-Communist convictions developed over the previous five years were now convincing them to intervene and this action led Australia into the "dilemma of the Vietnamese civil war."Communism was seen as an aggressive force to destroy the western society of capitalism and democracy.
In 1945, there was one Communist state in the world, Russia by 1949 with the establishment of the Communist Peoples' Republic of China led by Chairman Mao, 11 countries were now communists.
For many Australians who had lived through World War 2, there was greater fear because they could see the parallels between the imminent threats of invasion through communism with the threat that the Japanese had produced 20 years earlier.
The same sort of pattern could be seen with the domino effect, how they were slowly jumping from country to country gaining more power and Australia would be at threat if action weren't taken.
This formalised the relationship between Australia, America and New Zealand and one would come to the other's aid in the event of attack.
The Malayan Emergency (1948-60) was the only war the West won against insurgent communism.
It was feared that this "domino" action would eventually lead to Australia's shores and then the policy of forward defence would mean the war would be in Darwin instead of Vietnam and Australia would be in imminent danger.
The involvement of Australian forces in Vietnam was a continuing development of increasing commitment that took place over a period of several years against a background of Cold War concerns with regional security and fear of Communist expansion.
The American presence in South Vietnam was seen as an extension of the principle of containment.
That principle had it that in the interests of avoiding a global war no great attempt would be made to liberate countries, which had fallen to communism, but the spread of communism, inevitably by dictatorial means, would be resisted.