The Know Nothings were a nativist political movement in the United States in the 1850s, officially known as the Native American Party before 1855, and afterwards simply the American Party. Members of the movement were required to say "I know nothing" whenever they were asked about its specifics by outsiders, providing the group with its colloquial name.

The 1856 United States presidential election was the 18th quadrennial presidential election, held on Tuesday, November 4, 1856. In a three-way election, Democrat James Buchanan defeated Republican nominee John C. Frémont and Know Nothing nominee Millard Fillmore. The main issue was the expansion of slavery as facilitated by the Kansas–Nebraska Act of 1854. Buchanan defeated President Franklin Pierce at the 1856 Democratic National Convention for the nomination. Pierce had become widely unpopular in the North because of his support for the pro-slavery faction in the ongoing civil war in territorial Kansas, and Buchanan, a former Secretary of State, had avoided the divisive debates over the Kansas–Nebraska Act by being in Europe as the Ambassador to the United Kingdom.