Here are some politically themed children and YA books (fiction and nonfiction) that are informative, entertaining and/or thought-provoking.
10 Children and YA Books to Read During Election Season:
1. Hero Type, by Barry Lyga
2. Animal Farm, by George Orwell
3. The President's Daughter, by Ellen Emerson White
4. Nothing But the Truth, by Avi
5. Freedom Walkers, by Russell Freedman
6. Two Miserable Presidents: Everything Your Schoolbooks Didn't Tell You About the Civil War, by Steve Sheinkin
7. Election, by Tom Perrotta
8. The Watsons Go to Birmingham--1963, by Christopher Paul Curtis
9. Max for President, by Jarrett J. Krosoczka
10. Vote for Larry, by Janet Tashjian
Obviously, there are many many more options out there and I definitely limited myself to American politics. Why, I even forgot to mention Katherine DeBrecht's Help! Mom! There Are Liberals Under My Bed!
Bonus Adult Books that are also applicable:
The Casual Vacancy, by J.K. Rowling
More at the Broke and the Bookish!