Australia got involved in the vietnam war because,they wanted to protect themselves from communism and also support other countries that were involved in the war. They had some policies that they wanted to accomplish so that they can overcome the war. For more information, go to http://vietnam-war.commemoration.gov.au/.
We got involved in the war because our government at the time was so overwhelmed with the U.S.A and would do anything they were asked including sending conscripts to war without hesitation. But the if you were brave enough to say no to the government , you would get 6 months jail, the moral of the story is if they had enough guts to say no in the first place and goto jail for 6 months the government would have bowed to the pressure and no sent soldiers their after all you can't put 10,000 objectors into jail, thier aint enough room.