In 1997, Cohen co-founded the Project for the New American Century (PNAC), which was a center for prominent neoconservatives. He has been a member of the Defense Policy Board Advisory Committee, a committee of civilians and retired military officers that the U.S. Secretary of Defense may call upon for advice, that was instituted during the administration of President George W. Bush. He was put on the board after acquaintance Richard Perle put forward his name. Cohen has referred to the War on Terrorism as "World War IV". In the run-up to the 2003 invasion of Iraq, he was a member of Committee for the Liberation of Iraq, a group of prominent persons who pressed for an invasion.