The rapidity of the Japanese amphibious blitzkrieg in South East Asia raised understandable fears of invasion in Australia. In fact with four fifths of the Imperial Japanese Army tied down in China and a possible Soviet thrust into Manchuria being feared, the japanese military vetoed plans by middle ranking navy staff officers to prevent Australia being used as a base for strategic counterattack by holding beachheads on the Cape York peninsular and northern Western Australia. It was felt that mission creep would see any such incursion degenerate into an unsustainable battle for the continent.The Battle of the Coral Sea and the defensive actions on the Kokoda Trail, at Milne Bay and in Timor did not in fact save Australia, although the men who fought them put their lives on the line with that objective in mind, and prevented strenuous Japanese efforts to stabilise their southern perimeter with a view to preventing aerial interdiction of the supply of Phillipine oil. The Battle of Midway was of much greater significance, breaking Japanese naval power. Australian security owed as much to comrades Mao Tse Tung and Stalin as to Uncle Sam.
Dockrill `Collins Atlas of 20th Century World History'