John Caldwell Calhoun (March 18, 1782 – March 31, 1850) was the 7th Vice President of the United States and a leading Southern politician from South Carolina during the first half of the 19th century. Calhoun was an advocate of slavery, states' rights, limited government, and nullification.

He was the second man to serve as Vice President under two administrations, (as a Democratic-Republican under John Quincy Adams and as a Democrat under Andrew Jackson), the first Vice President born after the American Revolution and the first Vice President to resign from office.

After a short stint in the South Carolina legislature, where he wrote legislation making South Carolina the first state to adopt universal suffrage for white men, Calhoun, barely 30, began his federal career as a staunch nationalist, favoring war with Britain in 1812. However, Calhoun's position changed in favor of states' rights following the "Corrupt Bargain" of 1824, by which Speaker of the House Henry Clay allegedly gave the Presidency to John Quincy Adams in exchange for the position of United States Secretary of State.