William Sebastian Cohen (born August 28, 1940) is a Republican politician from Maine. Cohen was born in Bangor, Maine.
Cohen was an attorney and law professor before entering politics. After several terms in the United States House of Representatives, he was elected to the United States Senate in 1978. He was reelected in 1984 and 1990 and served from 1979 to 1997. Both of Maine's current senators, Susan Collins and Olympia Snowe, worked for him. Snowe worked while he was in the House and Collins while he was in the Senate.
Cohen decided to retire in 1996 and Collins was elected to succeed him. Cohen was then Secretary of Defense in the cabinet of President Bill Clinton from 1997 to 2001. His appointment was interesting because Clinton was a Democrat, and Presidents usually appoint members of their own party to most cabinet positions. As Defense Secretary he played a large role in directing the United States military actions in Iraq and Kosovo.