Caspar Willard "Cap" Weinberger was an American politician, vice president and general counsel of Bechtel Corporation, and Secretary of Defense under President Ronald Reagan from January 21, 1981, until November 23, 1987, making him the third longest-serving defense secretary to date, after Robert McNamara and Donald Rumsfeld. He is also known for his role in the Strategic Defense Initiative and the Iran-Contra Affair.