Kremlin, during which he extracts KGB Chairman Gerasimov's wife and daughter from Leningrad after the Chairman decides to defect to the United States. This marks Clark's first published appearance. In Clear and Present Danger, he commands a U.S. Army black-ops unit carrying out a secret war against the Medellín Cartel in Colombia. When the government abandons the men for political reasons, Clark and Jack Ryan fly down to Colombia and rescue the survivors. This is the first time he interacts with Ryan. In The Sum of All Fears, he is Ryan's personal driver and bodyguard. Later in the novel, he is returned to the field for one operation, bugging the aircraft of the Japanese Prime Minister in Mexico City. During the operation, a terrorist bombing in Denver occurs and his mission is changed to intercepting the Palestinian terrorists trying to escape through Mexico, which he does successfully. He interrogates them and secures their confessions, then hands them over to the judicial system for eventual Islamic justice (execution by sword) in Riyadh. In Debt of Honor, he is again a field officer for the CIA's Directorate of Operations (DO). At the beginning of the novel, he and Domingo Chavez capture an Aidid-like African warlord, Mohammed Abdul Corp, and bring him to justice. Soon thereafter, they are sent to Japan to assess the national mood of the country, where Clark is undercover as a Russian reporter. When the situation turns into a war between Japan and the United States, they establish contacts with the opposition in the Japanese government and are also tasked to eliminate a pair of Japanese AWACS planes. Clark spends the first half of the next book, Executive Orders, serving as an instructor for CIA field officers in training. Early in the novel, Jack Ryan, the new President, issues a presidential pardon to John Terence Kelly for his several murders. This clears his name and personal honor, but he will continue his career as John Clark. Towards the end of the book, he and Chavez are returned to the field and ordered to discover who is responsible for an Ebola attack on the United States, an action they quickly trace to the new United Islamic Republic (comprising Iran and Iraq). With the cooperation of the Russian SVR, they are infiltrated into Tehran, where they laser-designate the home of UIR dictator Mahmoud Haji Daryaei so that Air Force stealth aircraft