There's no question that Americans are bitterly divided by politics. But in Partisans and Partners, Josh Pacewicz finds that our traditional understanding of red/blue, right/left, urban/rural division is too simplistic.

Wheels-down in Iowa--that most important of primary states--Pacewicz looks to two cities, one traditionally Democratic, the other traditionally Republican, and finds that younger voters are rejecting older-timers' strict political affiliations. A paradox is emerging--as the dividing lines between America's political parties have sharpened, Americans are at the same...