William R. Day, American jurist and politician, 36th United States Secretary of State (d. 1923)
William Rufus Day (April 17, 1849 – July 9, 1923) was an American diplomat and jurist who served as an associate justice of the Supreme Court of the United States from 1903 to 1922. Prior to his service on the Supreme Court, Day served as United States Secretary of State during the administration of President William McKinley. He also served as a United States Circuit Judge of the United States Court of Appeals for the Sixth Circuit and the United States Circuit Courts for the Sixth Circuit.