John Caldwell Calhoun (March 18, 1782 – March 31, 1850) was a leading politician and political theorist from South Carolina during the first half of the 19th century. A powerful intellect, Calhoun eloquently spoke out on every issue of his day, but often changed positions. Calhoun began his political career as a nationalist, modernizer, and proponent of a strong national government and protective tariffs. After 1840 he switched to states' rights, limited government, nullification and free trade. He is best known for his intense and original defense of slavery as a positive good, for his inventing the theory of minority rights in a democracy, and for pointing the South toward secession from the Union.