For all its importance as a policy tool around the globe, the study of public procurement has barely begun. The role of government purchasing in trade strategy, in particular, has been virtually ignored in the international political economy literature. We argue that government procurement increasingly serves as a weapon in the US arsenal of tools for sponsoring national champions, for securing the domestic front against foreign competitors, and for promoting exports via the penetration of foreign procurement markets. Whilst vigorously pressing for enlargement of procurement markets, the US is distinctive in having the most aggressive 'buy national' programs, which are enshrined in law and enforced in both formal and informal ways. Also at odds with its own liberal dictates, government procurement in the US involves a considerable amount of proactive state involvement and government-business cooperation.