(; April 23, 1791 – June 1, 1868) was an American politician who served as the 15th president of the United States (1857–1861), serving prior to the American Civil War.
A member of the Democratic Party, he served as the United States Secretary of State and in both houses of the U.S.
Congress representing Pennsylvania before becoming President.
Born in Cove Gap, Pennsylvania, Buchanan became a prominent lawyer and won election to the Pennsylvania House of Representatives as a Federalist.
In 1820, he won election to the United States House of Representatives, aligning with Andrew Jackson's Democratic Party.
He served as Jackson's Minister to Russia, then won election as a U.S.
senator from Pennsylvania.
In 1845, he accepted appointment as President James K.
Polk's Secretary of State.
He was a major contender for his party's presidential nomination throughout the 1840s and 1850s and was finally nominated in 1856, defeating incumbent President Franklin Pierce and Senator Stephen A.
Douglas at the 1856 Democratic National Convention.
Buchanan and running mate John C.
Breckinridge of Kentucky defeated Republican John C.
Frémont and Know-Nothing Millard Fillmore to win the 1856 presidential election.
President Buchanan supported the Dred Scott decision and joined with Southern leaders in attempting to admit Kansas to the Union as a slave state under the Lecompton Constitution.
In the process, he angered Republicans and alienated many Northern Democrats.
Buchanan held to his pledge to serve only one term and supported Breckinridge's unsuccessful candidacy in the 1860 presidential election.
Several Southern states seceded after Republican Abraham Lincoln won the 1860 election, and the American Civil War began just weeks after Buchanan left office.
He died in 1868 at age 77.
Historians fault him for his failure to address the issue of slavery and the secession of the Southern states and generally consider him to be one of the worst presidents in U.S.