This article explores the Cold War history of the Australia-U.S. alliance, and then uses this knowledge to contextualise more recent developments in the bilateral relationship. At several crucial moments in the first half of the Cold War, Australia disagreed with the U.S. about the wisdom of its policy toward China, and worked to moderate Washington's aggressive impulses. However, from the 1960s onwards, Australian leaders began to internalise a schema of alliance loyalty: they believed that only loyalty to the U.S. would ensure reciprocal loyalty from Washington. Although events have challenged the validity of this hypothesis, it became a powerful and pervasive influence which led, over time, to Canberra thinking less carefully about the costs and benefits of prospective alliance action. This intellectual lethargy explains why Canberra has found it difficult to adapt to a period of more intense strategic competition between China and the U.S today.