From Empire to Internationalism reveals how a defeated empire recast itself, in just fifteen years, as a peace-loving member of the international community. When Japan joined the United Nations in 1956, none of the welcoming delegates dwelled on its history of colonial rule and military conquest. Existing accounts explain its rapid reintegration into the global order through Cold War politics or a longer tradition of Japanese internationalism. Lori Watt offers a new account: The American-led dismantling of Japan's empire provided elites with a new vocabulary that allowed them to re-narrate its imperial past in terms associated more with former colonies than former empires. Watt traces this dynamic from postwar planning in Washington to Japan's eventual admission to the UN. She shows how leaders of a defeated nation appropriated a rhetoric of self-determination, popular sovereignty, and human rights, all concepts used by anticolonial nationalists elsewhere. Provocative and persuasive, From Empire to Internationalism offers a fresh perspective on how the vocabulary and practices of decolonization shaped the postwar international order.