Contrary to conventional accounts, the United States did not immediately adopt a set of sweeping commitments to Europe after World War II. Instead, it pursued a buck-passing strategy until the early 1960s that sought to craft Western Europe into an independent pole of power capable of balancing the Soviet Union largely without the assistance of the United States, thereby facilitating the withdrawal of U.S. troops from the continent. Only under President John F. Kennedy did the United States adopt a balancing strategy, making permanent forward commitments to the defense of Europe. A new theory of liberal ideas and foreign policy explains this shift. “Negative liberals,” who see freedom in terms of opportunity and minimal state intervention, adopted a buck-passing strategy to pass the costs of foreign policy to other actors and minimize state intrusion at home. “Positive liberals,” who see freedom as the exercise of capabilities and often welcome state intervention, had no such compunctions. Starting with Kennedy, positive liberals welcomed firmer balancing commitments in part as a measure to protect the liberal regimes that had emerged in Western Europe after World War II.