This dissertation asks how a punitive response to non-medical drug use came into force across the globe in the twentieth century. It argues that U.S. officials were the authors of that punitive approach. They forged it in response to opium smokers in their Philippine colony in the early 1900s as part of what they regarded as a modern and progressive solution to a moral and practical problem. The Philippine experience served in turn as the basis for a punitive model abroad. Washington organized international conferences pushing for ironclad clauses in treaties and sought to undercut attempts to keep non-medical drug use legal. The international outcome of these efforts was evident by the interwar years with the rise of a global punitive regime prompted by international treaties and effected through national legislation and reporting. The new regime survived an immediate challenge from foreign public health bureaucrats who proposed to deal with drug consumers as patients rather than prisoners. American officials overcame this challenge by advancing specialized incarceration as a cutting-edge form of addiction treatment. After the Second World War the U.S. government was more active than ever in promoting punishment. Congress imposed mandatory incarceration for illegal drug possession, while an assertive executive branch worked to consolidate the punitive approach overseas by pressuring non-compliant countries and tightening treaty terms. A global wave of drug consumerism among youth in the late 1960s posed the second serious challenge to the regime. While forcing a moderation in the penalties in the United States, drug consumerism did not overwhelm (or even significantly alter) the punitive regime. Most governments reacted by escalating penalties. The American punitive approach remained the international norm.