|Occupation(s)||U.S. Secretary of Defense|
|First Appearance||"The Clock" (mentioned)|
|Images of Caspar Weinberger|
Caspar Weinberger is the U.S. Secretary of Defense. Philip enlists a KGB agent named Annelise to take photographs of his study and he and Elizabeth discover that a bug can be planted in a clock in the study.
They discover that a meeting is to take place between Weinberger, British Prime Minister Margaret Thatcher and her defense secretary John Nott to discuss the Americans' proposed Strategic Defense Initiative. Weinberger and Nott are later heard discussing plans to build a missile shield.