James was the 11th President of the United States (1845–49). Polk was born in Mecklenburg County, North Carolina. He later lived in and represented Tennessee. A Democrat, Polk served as the 13th Speaker of the House of Representatives (1835–39)—the only president to have served as House Speaker—and the first of two (the other being Andrew Johnson) to serve as Governor of Tennessee (1839–41). Polk was the surprise (dark horse) candidate for president in 1844, defeating Henry Clay of the rival Whig Party by promising to annex the Republic of Texas. Polk was a leader of Jacksonian Democracy during the Second Party System.
Polk is often considered the last strong pre–Civil War president, having met during his four years in office every major domestic and foreign policy goal set during his campaign and the transition to his administration. When Mexico rejected the U.S. annexation of Texas (which Mexico considered part of its territory, despite the 1836 Texas Revolution), Polk led the nation to a sweeping victory in the Mexican–American War, which resulted in the cession by Mexico of nearly the whole of what is now the American Southwest. He ensured a substantial reduction of tariff rates by replacing the « Black Tariff » with the Walker tariff of 1846, which pleased the less-industrialized states of his native South by rendering less expensive both imported and, through competition, domestic goods. He threatened war with the United Kingdom over the issue of which nation owned the Oregon Country, eventually reaching a settlement in which the British were made to sell the portion that became the Oregon Territory. Additionally, he built an independent treasury system that lasted until 1913, oversaw the opening of the U.S. Naval Academy and of the Smithsonian Institution, the groundbreaking for the Washington Monument, and the issuance of the first United States postage stamp.