The presidency of James K. Polk began on March 4, 1845, when James K. Polk was inaugurated as President of the United States, and ended on March 4, 1849. He was a Democrat, and assumed office after defeating Whig Henry Clay in the 1844 presidential election. Polk left office after one term, fulfilling a campaign pledge he made in 1844, and he was succeeded by Whig Zachary Taylor. Despite his reliance on his cabinet, Polk involved himself in the minutiae of the various departments, especially regarding the military. The Walker Tariff would remain in place until the passage of the Tariff of 1857, staying in effect longer than any other tariff measure of the nineteenth century. The reduction of tariffs in the United States and the repeal of the Corn Laws in Great Britain led to a boom in Anglo-American trade and, in large part due to growing international trade, the economy entered a strong period of growth in the late 1840s.