Leslie Aspin Jr. (July 21, 1938 – May 21, 1995) was an American Democratic Party politician and economist who served as the U.S. representative for Wisconsin's 1st congressional district from 1971 to 1993 and as the 18th United States Secretary of Defense under President Bill Clinton from 1993 to 1994.
In Congress, Aspin had a reputation as an intellectual who took a middle-of-the-road position on controversial issues. He supported the Reagan administration regarding the MX missile and aid to the Nicaraguan Contras, but he opposed the B-2 bomber and the Strategic Defense Initiative. He played a major role in convincing the House to support the January 1991 resolution supporting the use of force by President George H. W. Bush against Iraq, after it invaded Kuwait.