"C" is for Calhoun, John Caldwell [1782-1850]. Congressman, secretary of war, secretary of state, vice president of the United States, United States senator. In 1810, Calhoun won a seat in Congress, thus beginning a long, distinguished, and controversial career in national politics. He was President Monroe's secretary of war and later vice president under John Quincy Adams and Andrew Jackson. Resigning from office, Calhoun was elected to the U.S. Senate where he became a national figure. He developed the doctrine of nullification as a constitutional mechanism to assert states rights against the power of the federal government. Calhoun spent the remainder of his career as the leading strategist of an evolving southern sectionalism. John Caldwell Calhoun stands second only to James Madison as an original political thinker among practicing politicians in American life.