John Caldwell Calhoun (1782-1850) was a leading United States 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 elected twice to the Vice Presidency, serving from 1825 until he resigned in 1832. He served in the United States House of Representatives (1810–1817) and in the U.S. Senate from 1832-1843. He served as Secretary of War (1817–1824) under 5th U. S. President James Monroe and Secretary of State (1844–1845) under 10th U. S. President John Tyler.