One author people don't talk about a lot is Doris Lessing. I only got into her earlier this year, but much of her work is political, or at least deals with politics as an issue. The novels from the Children of Violence series and The Golden Notebook contain some pretty painful indictments of communist groups from the 1930s-1950s. Not from a reactionary angle, but from someone deeply involved with the party in Rhodesia for at least a decade and for some of her time in England. She also touches on some feminist issues, though she dislikes being called a feminist writer. The novels I read also touched on issues of racial discrimination in colonial Africa, though my understanding is that's more the main subject of The Grass is Singing.
I also read some E.M. Forster a while back and was for some reason surprised by how much he dealt with the politics and class in Edwardian England. I mean, the love interest in Room With a View is the son of *gasp* a working class socialist, which the Merchant/Ivory adaptation kinda glosses over. Howard's End is pretty interesting from a political angle as well.
- I think Charles Dickens works best showed the importance of basic welfare and employment laws. - George Orwell, the dangers of state and propaganda - Shogun highlights the dodgy dealings and dirty politics in the world very well - His dark materials trilogy represents the dangers of religious institutions - Lastly I'd have to say Terry Pratchet discworld books. They may be very humourous and absurd but some of the observations are pretty accurate and astute.