Australiaâ€™s wartime security was imperilled by the failure of the Franco-British union. The proposal to merge the British and French Empires into a supra-national entity became a short-lived possibility in June 1940. This article examines why Australian Prime Minister Robert Menzies unconditionally endorsed the idea. Examining the proposal, and French territories surrounding Australia, demonstrates why Australia was invested in a continued French war effort and had much to gain from its union with Britain. The failure of the Franco-British union in Europe had damaging consequences for distant Canberra, which, unprepared for war, became surrounded by potentially hostile territories.