In writing about Henry Adams recently, I was intrigued by a perennial conversation as to what are the best political novels. The project begins with defining what is a political novel. Surely it cannot be limited to fictions about the elctoral process.
All human society has political content, and novels have to be embedded in a human society. Even allegories like Lord of the Flies (children) and Animal Farm (critters) are about how to societal structures evolve and effect people — quintessentially political. What about Updike’s The Terrorist? There is very little conversation about political topics in it, but the core action on the book, and its core conundrums, are political.
With some trepidation, I offer a definition of the political novel: A book that concentrates on the structuring of human relationships in the public, non-intimate sphere. Maybe a bit pretentious, and a tad expansive. But a narrower definition risks excluding much of the novel’s power to comment on human society.
So, my list:

1984, By George Orwell: The force of this book lives in our daily language. Orwellian. 1984. The concepts remain as evocative today — 24 years after the fictional future imagined by Orwell — as it was during the height of the Cold War. And Orwell depicted a political society that can grow from overtly totalitarian soil, or in the loam of a frightened democracy recoiling from terrorism. Get it? It’s a powerful book, not a subtle one.

Burr by Gore Vidal: It’s just so damned much fun! An irresistible, and plausible, imagining of history, with a fabulous central character and a delightfully jaded view of politics and politicians.
Tinker, Tailor, Soldier, Spy, By John LeCarre: No one captured the bleak contest of the Cold War as well as LeCarre, and this was the best of his Smiley books. I like one description of his world as the struggle between the pretty bad (us) and the truly awful (them).
The Palliser Novels, By Anthony Trollope: I know, I know, they’re so darned long. But they’re wonderful. (Admission: I have gotten through only four of them so far.) All of the pettiness and ambition of the human scramble of politics. Great stuff.
Democracy, by Henry Adams: A tad moralistic, but an enduring tale of disenchantment and venality.
I know I’ve left lots out, but I mostly had reasons. I recently tried to reread All the Kings Men by Robert Penn Warren, and it seemed like a lot of self-important bloviation. Primary Colors by Anonymous (Joe Klein), is great fun, but mostly about the mechanics of campaigning. And there are the heavy existentialist novels (Camus’ The Stranger,) and the bleak soviet renderings (Solzhenitsyn’s Cancer Ward ). Great, but work, don’t you know? Then there are all the ones I haven’t read yet.
For some other takes on this question, you can look into Deep Thoughts from Christopher Lehmann about why American political novels are so shallow http://www.washingtonmonthly.com/features/2005/0510.lehmann.html, or NPR’s whack at this, http://www.npr.org/templates/story/story.php?storyId=1890288, or even the Wall Street Journal’s take,http://politicalwire.com/archives/2006/08/27/the_five_best_political_novels.html