Tom Clancy is a writer who got a lot of praise for most of his early books, and this is one of those books that rightly justify that praise.
The story is set during the twilight years of the Cold War, but focuses little on it, instead focusing on the War on Drugs. Blending elements of the Iran-Contra scandal into the mix, we get a story of the US government wanting to do anything to curb the drugs trade, and in the process becoming corrupted at almost every level to do so, with high officials in many law and intelligence agencies willing to circumvent the law for a cause they deem so righteous they consider their actions justified considering the ends to the means.
Jack Ryan enters the picture at this point, slowly but surely discovering the scandal and illegal actions, and while sympathetic to the goal, finds himself having to both put an end to the corruption while not destroying the entire government in the process, a task made difficult because while he tries to end the drug war actions that are stepping over the law, he finds himself forced to bend the law himself in order to stop others from outright breaking it.
It's a fascinating story of greying morality, where even the good guys resort to evil means to serve justice, and the tale has a recurring theme of "how evil good can be", and how worrying that can be when the cause is just but the means are anything but.
I'd highly recommend this story to anyone who wants to ponder the same moral questions, as well as read one of Clancy's best novels.