World War II had a significant impact on the trajectory of postrevolutionary Mexican development. Pressure from the United States for collaboration in defense efforts and the ambivalence of the Mexican public toward an active role in the conflict posed challenges. Yet the crisis atmosphere created by the war allowed the country’s leaders to insist upon a policy of national unity. The Ávila Camacho administration was thus able to maintain a broad political coalition as it took Mexico formally into the war on the side of the Allies in 1942 and then gradually expanded the scope of the country’s participation in the conflict. Wartime conditions prompted Mexico to expand its capacities and make new demands on citizens; they served as well to accelerate the professionalization and depoliticization of the armed forces. In economic terms, the war disrupted trade with Europe but spurred US demand for the strategic outputs of Mexican mines and farms and Mexican labor. The unavailability of previously imported goods provided an impetus for a process of industrialization that would continue into the postwar period, but many workers saw their living standards fall as wartime inflation eroded their real wages. Mexico emerged from the war with a claim to regional leadership, much-improved relations with Washington, a rapidly growing industrial sector, and a political landscape considerably more stable and consolidated than it had been in the two decades immediately following the Mexican Revolution.