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.

Full story: Political divide between coasts and Midwest deepening, midterm election analysis shows