John Cabell Breckinridge (January 16, 1821 – May 17, 1875) was an American lawyer, politician, and soldier. He represented Kentucky in both houses of Congress and became the 14th and youngest-ever vice president of the United States. Serving from 1857 to 1861, he took office at the age of 36. He was a member of the Democratic Party, and ran for president in 1860 as a Southern Democrat. He served in the U.S. Senate during the outbreak of the American Civil War, but was expelled after joining the Confederate Army. He was appointed Confederate Secretary of War in 1865.

The 1860 United States presidential election was the 19th quadrennial presidential election, held on Tuesday, November 6, 1860. In a four-way contest, the Republican Party ticket of Abraham Lincoln and Hannibal Hamlin won a national popular plurality, a popular majority in the North where states already had abolished slavery, and a national electoral majority comprising only Northern electoral votes. Lincoln's election thus served as the main catalyst of the states that would become the Confederacy seceding from the Union. This marked the first time that a Republican was elected president. It was also the first presidential election in which both major party candidates were registered in the same home state; the others have been in 1904, 1920, 1940, 1944, and 2016.

The United States had become increasingly sectionally divided during the 1850s, primarily over extending slavery into the western territories. The incumbent president, James Buchanan, like his predecessor, Franklin Pierce, was a Northern Democrat with Southern sympathies. Buchanan also adamantly promised not to seek re-election. From the mid-1850s, the anti-slavery Republican Party became a major political force, driven by Northern voter opposition to the Kansas–Nebraska Act and the Supreme Court's 1857 decision in Dred Scott v. Sandford. From the election of 1856, the Republican Party had replaced the defunct Whig Party as the major opposition to the Democrats. A group of former Whigs and Know Nothings formed the Constitutional Union Party, which sought to avoid disunion by resolving divisions over slavery with some new compromise.

The 1860 Republican National Convention in Chicago nominated Abraham Lincoln, a moderate former one-term Whig Representative from Illinois. Its platform promised not to interfere with slavery in the South but opposed extension of slavery into the territories. The 1860 Democratic National Convention adjourned in Charleston, South Carolina, without agreeing on a nominee, but a second convention in Baltimore, Maryland, nominated Illinois Senator Stephen A. Douglas. Douglas's support for the concept of popular sovereignty, which called for each territory's settlers to decide locally on the status of slavery, alienated many radical pro-slavery Southern Democrats, who wanted the territories, and perhaps other lands, open to slavery. With President Buchanan's support, Southern Democrats held their own convention, nominating Vice President John C. Breckinridge of Kentucky. The 1860 Constitutional Union Convention, which hoped to avoid the slavery issue entirely, nominated a ticket led by former Tennessee Senator John Bell.

Lincoln's main opponent in the North was Douglas, who won the popular vote in Missouri, electoral votes in New Jersey, and the second highest popular vote total nationally. Douglas was the only candidate in the 1860 election to win electoral votes in both free and slave states. In the South, Bell won three states and Breckinridge swept the remaining 11. Lincoln's election motivated seven Southern states, all voting for Breckinridge, to secede before the inauguration in March. The American Civil War began less than two months after Lincoln's inauguration, with the Battle of Fort Sumter; afterwards four further states seceded. Lincoln would go on to win re-election in the 1864 United States presidential election. The election was the first of six consecutive Republican victories. Despite Lincoln's commanding victory, this was the first election in American history in which the winner has failed to win his home county, with Lincoln narrowly losing Sangamon County to Douglas. However, he would win Gasconade County which, as of the 2020 United States presidential election, has voted Republican ever since, marking the beginning of the longest active voting streak for any party at the county level.