A look at the life of Jack Ryan within the two books we (Stefan and Jason) read, along with some in-between details filled in from the books between those (which Stefan also read).
While the reason wasn't discussed in our books, we do know that Ryan served a number of years (completing six tours) in the Marines. His service ended in a helicopter crash in which he was severely injured.
Almost like the medicine for his recovery, Ryan begins teaching at the Annapolis Naval Academy in Maryland. It's the perfect place for him to continue his research, waiting for his next steps.
After publishing a book on the history and significance of military strategy and tactics, the CIA becomes curious in Ryan. His vast knowledge, ability to research and analyze in depth, and history of service makes him an ideal recruit for the CIA, at least in the eyes of Deputy Director of the CIA James Greer.
No longer in the Marines but once again in the service of the government, this time Ryan takes a more discreet role in international relations. He is now part of the nuclear ballet between Russia and the United States (or the West).
Before The Red October, Jack Ryan ascends the CIA's ladder of trust by first saving members of the British Royal Family and then helping Russian defectors escape Russia through a daring mission. This put him in a position to serve in critical roles within the CIA that would put him in contact with higher-level Russians. His character is clearly reaching for something bigger.
Jack Ryan is a CIA analyst with strong ties to the British Intelligence Agency; Being a part of this joint American-British liaison is what leads him on his first mission. An ordinarily mundane task that nearly scales up to nuclear war. He succeeded in trading some British intelligence on a new Russian sub in exchange for some American technology, and was just waiting to buy his daughter a Skiing Barbie, meet up with his boss, and have a chat with his good buddy Skip at the US Naval Academy. That's just who he is, a family guy with no huge responsibilities.
As Jack continues to work on the case of the Red October, he comes to realize that he is the only one with the skills to complete the mission. With his experience in the naval field and having personally met the submarine's commander Marko Ramius at an embassy function, he knows what kind of person he is, and is ultimately the one to determine that he intends to defect. Despite never having done this kind of high-stakes on the field work, he selflessly leads the charge to bring Ramius and his submarine to the United States.
Another characteristic present throughout the story is that Jack believes that everyone should be given a chance to come to America. He understands that the Soviets brainwash their people into believing that it's a horrible place, but he still tries to help them. An example of this happens near the end of The Hunt for Red October, where even after a Soviet intelligence officer kills one of his own men attempting to defect and shoots an American Lieutenant, he still tries to reason with him that he can come to the United States and start a better life. This is a continuation of the traits he exemplified in Red Rabbit.
While Jack has been on contained adventures deep within the airtight CIA, the Cold War has been "raging" around him. His bosses (in the CIA) and the president himself have decided to place him in a position critical to the denuclearization efforts near the end of the "conflict." Meanwhile, deep within the Kremlin, the CIA's top source (CARDINAL) has uncovered something far more dangerous than nuclear weapons. This latest adventure is pitting Jack Ryan and his vices against a new challenge that is far more dangerous to the security of the free West than anything he has done before. As is the progression of these books, the pressure against his character and brilliance is ever increasing.
Between information hand offs, CARDINAL can only find escape in his civilian vodka.
More unlike the other books, Cardinal features far more screen time with distant characters, like CARDINAL himself. After an introduction to the plot, the challenges of willpower, grief, and determination that CARDINAL, an aging Stalin Era general, faces are laid bare. As the book progresses, the plot takes a far more emotional undertone than Clancy readers may be accustomed to.
The Cardinal of the Kremlin ends, and so does the USSR's efforts to compromise the United States.
Once again, Ryan doesn't leave the scene conveying a sense of satisfaction and loss of appetite for honest effort and the struggle for national security. He is clearly prepared to continue climbing the exponentially more difficult ladder of responsibility within the government and international relations. He even ascends in media attention.