Australia joined with the United Kingdom in declaring war on September 3, 1939 on Germany. New Zealand did so also, preferring to send a separate letter to demonstrate independence. New Zealand and Australian units served in North Africa, Italy, and Greece and rendered good service. When the Japanese attacked around Asia and the Pacific in December 1941, the overseas units were rushed home as part of the agreement Australia and New Zealand signed with England at the start of the war. Some were sent to Singapore, where they were surrendered on February 17, 1942. Two days later, the Japanese bombed Darwin, sinking twenty-six ships.
England could no longer guarantee their defense due to the war in Europe. In December 1941, the Australian government, led by Prime Minister John Curtain until his death in July 1945, publicly asked for American assistance. That assistance would come with a price that Australia could not imagine in 1941.
In March 1942 MacArthur, fresh from his retreat in the Philippines, took stock of his new command, Supreme Commander Southwest Pacific. He found that he had few of his countrymen to command. Until early 1944, the Australians would make up the bulk of his forces. The friction between MacArthur and his Australian subordinates would compromise the Allied operations in New Guinea.
Australia and New Zealand provided the Allies, especially Britain, with many needed supplies. New Zealand rationed its own food supply to increase the amount that could be sent to England.
In November 1942, while the Allies were landing in North Africa, MacArthur landed green American troops on Buna beach in New Guinea. They were immediately met with heavy fire, and discipline broke down. MacArthur’s reaction was to declare an American victory, and send in his experienced Australian troops. They were successful, but taking Buna had left a bitter taste in the Australian diggers’ mouth. MacArthur was a bitter pill to swallow.
MacArthur recognized the importance of propaganda, and he often claimed American involvement in what should have been Australian laurels. Australians marched across the Kokoda Trail in New Guinea, took Kokumbona, and were landing along the New Guinea backbone.
By 1944, the New Guinea campaign was finally becoming an American operation. 500,000 American servicemen were in Australia, and both governments contemplated banning American-Australian marriages. Eventually 12,000 Australian women married Americans.
Australia’s Armed Forces tried to promote volunteerism. The Australian constitution prohibited compulsory service overseas. By war’s end, some 95% of her army and 100% of her navy were volunteers and could serve in New Guinea or Europe.