Richard A. Clarke began his federal service in 1973 in the Office of the Secretary of Defence as an analyst on nuclear weapons and European security issues.
In the administration of Ronald Reagan, Mr Clarke was the Deputy Assistant Secretary of State for Intelligence.
In the George H W Bush administration, he was the Assistant Secretary of State for Politico-Military Affairs and then a member of his NCS staff.
He served for eight years as a Special Assistant to President Clinton and served as National Coordinator for Security and Counterterrorism for both President Clinton and President George W Bush.
From 2001 to 2003, he was the Special Advisor to the President for Cyberspace Security and Chairman of the President's Critical Infrastructure Protection Board.
Subsequently Clarke became chairman of Good Harbor Consulting.