When the war first broke out in 1939 the Australian Prime Minister Robert Menzies immediately sent Australian troops overseas to the middle east to help the British empire as Australia still considered itself part of the British Empire. But then in 1942 Prime Minister Curtin made the decision to pull Australian troops out of the war and come back to Australia to fight against Japan. Because the Japanese also brought the United States into the war Australians were forced to make alliance with the United states. The relationships between Britain and America changed over the war because of the invasion of the Japanese.
The Japanese first brought the pacific and the united states into the war when they attacked Pearl Harbour on the 9 December 1941. Australian Prime Minister Curtin decided to bring back the 6th and 7th Divisions from the Middle east to Indonesia. The British government understood Australia's decision to do this but the British Prime Minister Churchill ordered that some of the troops be diverted to reinforce British troops fighting in Burma.
Curtin went against the British and ordered that the troops return to Australia to defend their country. The British felt the loss of the Australians when in Tobruk they were forced to surrender because the 9th division left.
Before the Australian troops had arrived however the Australian were in great danger as the Japanese had made effective progress in their advancements to conquer the pacific. Prime Minister Curtin turned to the United States for alliance. The American General Douglas Arthur became supreme commander of the South-west Pacific after the American troops began arriving in Australia from December 1941. So many Americans had gone through Australian services during the war that by the end of the war more then one million Americans had passed through Australia.