sentences:  His predecessor as consul, Frank Carlucci, was later to become Secretary of Defense, and his successor, Thomas R. Pickering, was later to become Ambassador to the U.N..
  
  Matlock's next assignment was as Deputy Chief of Mission in the capital of Tanzania, Dar es Salaam.Even in Africa, knowledge of Soviet Affairs proved useful.With Leonid Brezhnev in power, Soviet foreign policy as of 1968 was dictated by the Brezhnev Doctrine, which held that, once a country became Communist, it was never to leave the Soviet sphere of influence.