This chapter explains the difference in Australian balance of threat (BOT) perceptions of China, that is, the so-called "China gap", as the result of Australian policy thinking – in contrast to Japan and the United States – remaining in a security dilemma over its perceptions of China's strategic character and intentions. It adapts Victor Cha's "quasi-alliance" model of cooperation between states allied to common patron to explain the growing levels of Australia-Japan security cooperation despite the different BOT perceptions that inform the China gap between Australia and Japan. The current signs are that China's choice already has been made and, as consequence, the "China gap" in Australian and Japanese perceptions will narrow rather than widen. Contemporary Australian foreign policy debate is focused on how much deeper the Australia-Japan security relationship can or should become given Australia's successful bilateral relationship with Japan, its substantial economic relationship with China, and the longstanding importance of the Australia, New Zealand, United States alliance.