Results from November's midterm elections have exposed a deepening political divide between cities on the coasts and the less-dense areas in the middle of the country.

The Republican Party's big gains in the House came largely from districts that were older, less diverse and less educated than the nation as a whole. Democrats kept their big majorities in the cities.

That's a contrast to the last GOP wave in 1994, when Republicans' share of the vote was consistent inside and outside metropolitan areas, according to a Washington Post analysis. That year, Republicans captured seats in a broader array of places.

The analysis, based on a review of the House vote in counties across the country in both years, has good and bad news for both parties.

The Obama coalition remained intact. Democrats remained strong in areas with the party's core of minorities and higher-educated whites. But movement of white working-class voters away from the party is a concern for Democrats, especially because of President Obama's traditional weakness with those voters.

Republicans' success with the blue-collar vote and the high enthusiasm of the tea party gives it a fired-up base headed into 2012. But in a presidential election with higher turnout, the party might have trouble winning a majority with those voters alone. It certainly can't rely on that bloc to carry the party into the future.

Democrats largely held on to their high share of the vote in the country's densest places. The party captured 54 percent in counties with populations of more than 500,000 people, compared with only 49 percent in 1994. In smaller counties, Democrats' share of the vote slid to 39 percent this year from 43 percent in 1994.

Much of the reason for the Democrats' decline in less-dense areas can be attributed to the party's trouble attracting white, working-class voters. Exit polls showed that Democrats lost white voters without a college degree - one way to measure blue-collar voters - by almost 30 percentage points in House races.

The Republican victories were concentrated in districts with those voters. In the 63 districts that Republicans won, 39 were older than the nation as a whole and 40 had a higher percentage of people without college degrees. The starkest difference was in racial composition: 47 of the 63 districts won by the GOP had a higher percentage of white people than the national average.

While the party's strength in working-class areas was impressive, it's little insurance for the future - the share of those voters has been shrinking since World War II.

"Republicans do the best in areas that are typically not growing very fast and don't look like the present, or certainly the future, of the country," said Ruy Teixeira, a Democratic political strategist with the Center for American Progress.

The Republican Party picked up 23 seats in the South and 19 in the Midwest. Rural areas of Pennsylvania and New York State were also big sources of wins.