James K. Polk

James Knox Polk (; November 2, 1795 – June 15, 1849) was the 11th president of the United States, serving from 1845 to 1849. A protégé of Andrew Jackson and a member of the Democratic Party, he was an advocate of American expansionism and Jacksonian democracy. Polk saw Texas join the Union in his first year in office, one of the precipitating causes that soon led the U.S. into the Mexican–American War. The settlement of that war expanded American territory to the Pacific Ocean. During his term, the dispute over the Oregon Territory with the United Kingdom was resolved as well, creating the present U.S.-Canadian boundary.

After building a successful law practice in Tennessee, Polk was elected to its state legislature in 1823 and then to the United States House of Representatives in 1825, becoming a strong supporter of Jackson. Following his tenure as chairman of the Ways and Means Committee, he became Speaker of the House in 1835, the only person to serve both as Speaker and U.S. president. Polk left Congress to run for governor of Tennessee, winning in 1839 but losing in 1841 and 1843. He was a dark-horse candidate in the 1844 presidential election as the Democratic Party nominee. Polk entered his party's convention as a potential nominee for vice president but emerged as a compromise to head the ticket when no presidential candidate could gain the necessary two-thirds majority. In the general election, he narrowly defeated Henry Clay of the Whig Party and pledged to serve only one term.