James K. Polk

James Knox Polk was elected president in 1844 in a prosperous period of U.S. history. He presided over the Mexican-American War (1846–48) and was responsible for expanding the nation with the addition of land that today comprises nine western states.

Polk was born on November 2, 1795, on a small farm in North Carolina , in an Irish American family. In his youth, he helped his father manage large local farms. He later graduated from the University of North Carolina at the top of his class. Two years later, he became a lawyer and soon began his political career with the Democratic Party of Tennessee . His friendship with Tennessee politician and future U.S. president Andrew Jackson (1767–1845; served 1829–1837) allowed Polk to move up quickly in politics. He was elected governor of Tennessee in 1839.

Dark horse candidate

Running as a “dark horse” (a political unknown) in the presidential election of 1844, Polk narrowly defeated the Whig Party leader Henry Clay (1777–1852). During the campaign, Polk forcefully asserted that it was the manifest destiny (God-given mission) of the United States to expand its borders. Once in office, in 1846 Polk acquired from England a large section of the northwest known as the Oregon Territory. The acquisition was won peacefully, although Polk did not gain as much territory as he had hoped.

War with Mexico

Mexico frustrated Polk's territorial ambitions. Although the Republic of Texas had won its independence from Mexico, the Mexican government refused to acknowledge it as an independent state and threatened war if the United States annexed Texas (added it to the country). Nonetheless, right before Polk took office, Congress had voted to annex Texas. Increasing the tension, Polk sent his ministers to Mexico to try to purchase the California and New Mexico Territories as well. When the Mexican president refused to see his ministers, Polk sent U.S. forces down to the Rio Grande River, the disputed border area. The conflict turned into the Mexican-American War. After the war, the victorious United States acquired Texas and much of the territory of present-day Arizona , California, Colorado , Nevada , New Mexico, Utah , and Wyoming .

The addition of new territory appealed to the American public, but it also inflamed the bitter dispute over slavery . One of the most explosive issues was whether the new territories would be admitted to the Union as slave states or free states. Polk, a slaveholder, sought compromise. He attempted to revive the Missouri Compromise of 1820, whereby slavery was prohibited in any new territories that lay above the latitude 36 degrees 30 minutes north, a line drawn across the map dividing North from South. But by 1848, the emotional and economic issues of slavery had become so intense that this compromise was unacceptable to both the North and the South.

During Polk's single term as president, the size of the United States increased by about 50 percent, providing needed land for farming, homesteading, and mining development. It was a watershed for U.S. westward expansion , encouraging one of the greatest population movements in U.S. history, but it was also a major factor in the bitter conflict leading up to the American Civil War (1861–65).

Polk's health was undermined by overwork during his term as president. He died in 1849, less than four months after leaving office.