Ideological justifications for the Vietnam war?
Vietnam was the second "hot" battle of the cold war (korea was the first). Had not the "Cold War" been in effect, the US MAY not have had very much justification for it's involvement. The US also operated "anti-communist" missions in Central/South America (e.g. Che Guevara). But, Vietnam was closer to the Communist Superpowers, and more easily supplied...the communist insurgency in Central/South America could NOT re-supply so easily, so they fizzled out (with US Gov't support). Without "Supplies" wars cannot be fought.
Yes, Australia fought in the Vietnam war on the side of the capitalists. They joined the war as a coalition with the US as a proxy war of the Cold War, and fought against the Vietcong and communists in an effort to prevent the Domino effect, an ideological security issue. Furthermore, Australia joined to retain the special Great and Powerful Friends relationship it has with the US in its usual sychophantic manner.