John Cornelius Stennis (August 3, 1901April 23, 1995) was an American politician who served as a U.S. Senator from the state of Mississippi. He was a Democrat who served in the Senate for over 41 years, becoming its most senior member for his last eight years. He retired from the Senate in 1989, and is, to date, the last Democrat to have been a U.S. Senator from Mississippi. Furthermore, at the time of his retirement, Stennis was the last United States Senator to have served during the Presidency of Harry Truman.