A historian traces the origins of the modern law-and-order state to a surprising source: the liberal policies of the New Deal. Most Americans remember the New Deal as the crucible of modern liberalism. But while it is most closely associated with Roosevelt’s efforts to end the Depression and provide social security for the elderly, we have failed to acknowledge one of its most enduring legacies: its war on crime. Crime policy, Anthony Gregory argues, was a defining feature of the New Deal. Tough-on-crime policies provided both the philosophical underpinnings and the institutional legitimacy necessary to remake the American state. New Deal Law and Order follows President Franklin Roosevelt, Attorney General Homer Cummings, and their war on crime coalition, which overcame the institutional and political challenges to the legitimacy of national law enforcement. Promises of law and order helped to manage tensions among key Democratic Party factions—organized labor, Black Americans, and white Southerners. Their anticrime program, featuring a strengthened criminal code, an empowered FBI, and the first federal war on marijuana, was essential to the expansion of national authority previously stymied on constitutional grounds. This nascent carceral liberalism both accommodated a redoubled emphasis on rehabilitation and underwrote a massive wave of prison construction across the country. Alcatraz, an unforgiving punitive model, was designed to be a “symbol of the triumph of law and order.” This emergent security state eventually transformed both liberalism and federalism, and in the process reoriented the terms of US political debate for decades to come.