US National Security Advisor from November 3, 1975 to January 20, 1977 under President
Gerald Ford and January 20, 1989 to 1993 under President
George Bush, the only person to serve as National Security Advisor under two different presidents. Also served as Deputy National Security Advisor under President
Richard Nixon and President Ford beginning in 1973 through his promotion to National Security Advisor by President Ford in November 1975.