This article explores who was ultimately responsible for the War of 1812. By applying the three-phase model of the emergence of nationalism (from an elite to a mass phenomenon) to the political situation in the United States from 1809 to 1812, it seeks to reconcile the historiographical debate between those who consider President Madison the driving force behind the movement toward war and those who argue that the war movement was anchored in the legislature. Though Madison and Jefferson had since 1803 taken an uncompromising stance toward the former mother country in order to promote an Anglophobic American nationalism, thereby escalating Anglo-American tensions, they wished to avoid outright war, as they feared that the requirements of war could overwhelm the young and fragile American republic. By 1811, however, public opinion, incited by the Republicans' persistent anti-British foreign policies, clamored for armed confrontation. A majority of Americans consequently elected Republicans to Congress who were willing to vote for a declaration of war. Yet Congress was reticent to declare war until Madison officially recommended this step, believing that a war waged without the administration's support would not succeed. Against his personal inclination, Madison opted to seek war to remain in control of American nationalism and to ensure, as a wartime president, that the waging of war would not undermine America's republican form of government. American nationalism had become a mass movement, assuming a dynamic of its own that became increasingly difficult to control. The onset of the War of 1812 was thus partly due to the pressure exerted by a rising populist nationalism that brought the so called war hawks into Congress, and partly due to the Madison administration's bid to remain in control of the political process.