Since you already have, I thought I'd just add my thoughts. I bought it to read during a recent business trip. As it happened, the guy next to me on my flight was a Business History professor at University of Maryland. He saw me reading it and told me that it was required reading for history majors at the University.
I found the historical fiction very interesting and a "what if" scenario that could have changed our course of history. I wish there had been more fleshing out of the larger context of the books primary thrust, that of Lindberg's Presidency and how that would have impacted the general society. Roth spends too much time with the familial impact of the narrator...who had lots of issues not really germane to the story.
I also agree with SheilaT that the ending was rushed and forced back to the path of actual history....I really think if Lindbergh had been elected we'd have continued well onto the path of fascism with a whole different history than what we have actually experienced.
But overall, I give it a hearty thumbs up, particularly in context with events happening today. I found Lindbergh's actual Des Moines speech really interesting in context with our position on no war today. It's really worth a read:
http://www.pbs.org/wgbh/amex/lindbergh/filmmore/reference/primary/desmoinesspeech.htmlInteresting historical note that the isolationist organization, "America First" was originated at Yale University. I'm surprised that Roth didn't bring in Prescott Bush into this novel...he certainly deserved some attention in this story plot.