Lewis Cass (October 9, 1782 – June 17, 1866) was an American military officer, politician, and statesman. He represented Michigan in the United States Senate and served in the Cabinets of two U.S. Presidents, Andrew Jackson and James Buchanan. He was also the 1848 Democratic presidential nominee. A slaveowner himself, he was a leading spokesman for the Doctrine of Popular Sovereignty, which held that the people in each territory should decide whether to permit slavery.