A wide-ranging history of modern America that argues that free trade has been an engine of US foreign policy and the key to global prosperity. Surprisingly, exports and imports, tariffs and quotas, and trade deficits and surpluses are central to American foreign relations. Ever since Franklin D. Roosevelt took office during the Great Depression, the United States has linked trade to its long-term diplomatic objectives and national security. Washington, DC saw free trade as underscoring its international leadership and as instrumental to global prosperity, to winning wars and peace, and to shaping the liberal internationalist world order. Free trade, in short, was a cornerstone of an ideology of "capitalist peace." Covering nearly a century, Capitalist Peace provides the first chronologically sweeping look at the intersection of trade and diplomacy. This policy has been pursued oftentimes at a cost to US producers and workers, whose interests were sacrificed to serve the purpose of grand strategy. To be sure, capitalists sought a particular type of global trade, which harnessed the market through free trade. This liberal trade policy sought the common good as defined by the needs, aims, and strengths of the capitalist and democratic world. Leaders believed that free trade advanced private enterprise, which, in turn, promoted prosperity, democracy, security, and attendant by-products like development, cooperation, integration, and human rights. The capitalist peace took liberalization as integral to cooperation among nations and even to morality in global affairs. Drawing on new research from the Reagan, George H.W. Bush, Clinton, and George W. Bush presidential libraries, as well as business/ industry and civic association archives, Thomas W. Zeiler narrates this history from the road to World War II, through the Cold War, to the resurgent protectionism of the Trump era and up to the present. Offering a new interpretation of diplomatic history, Capitalist Peace shows how US power, interests, and values were projected into the international arena even as capitalism brought both positive and negative results to the global order.