Perle has served as an advisor to multiple Republican U.S. Presidential administrations.

He is described as a neoconservative, and has been a staunch advocate of American military interventionism and a comprehensive presence on the world stage.

• He served as head of the Defense Policy Board Advisory Committe during the early administration of President George W. Bush, serving as a key architect of the 2003 invasion of Saddam Hussein's Iraq.

• He previously served as Assistant Secretary of Defense for Global Strategic Affairs under President Ronald Reagan.