Gilpatric was not always so dovish. He often took a hard line against the Communist threat, and was not above using force in other matters of international security. In the Eisenhower administration, Gilpatric headed a secret task force charged with "preventing Communist domination of Vietnam." Gilpatric argued forcefully for U.S. commitment to halt the Communist threat in South Vietnam. In his position with the Kennedy administration, Gilpatric later signed off on the overthrow of the Diem government. Gilpatric was also a member of a special task force which hatched "Operation Mongoose", a dirty tricks campaign aimed at destabilizing the government of Fidel Castro in Cuba.