The Cardinal of the Kremlin
The Cardinal is the codename for the highest-placed American agent in the Soviet Union, a man who knows the truth about the Soviet missile defense system and the plans the Iron Curtain nation has for it. He is marked for elimination by the KGB. Jack Ryan is the CIA agent in charge of getting him out alive. John Clark makes a small entry in the book as the man tasked with getting the Cardinal's wife and daughter out.