The Plot Against America by Philip Roth.
Excellent book. The premise sounds like something from Philip K. Dick...it supposes the the anti-Semitic Charles Lindbergh defeated Roosevelt in the 1940 election. But it has nothing to do with sci-fi. Anyway, it's an excellent read. I'm a big Roth fan. If you've never read him, you absolutely MUST read Portnoy's Complaint at some point. One of the three funniest book I've ever read (Heller's Catch-22 and John Kennedy Toole's A Confederacy of Dunces are the others).