A growing coalition of professionals, young people, and minorities has enabled Democrats to win four of the past six presidential elections, after two decades of Republican dominance. Geographically, however, the party is contracting.
Counties won by Democratic candidates for president
This coalition is more urban than the New Deal coalition that preceded it. President Obama won reelection in November carrying 1,000 fewer counties than Jimmy Carter in his 1976 win, and even fewer than Michael Dukakis in his 1988 loss. In modern times, no other candidate from either party has won the presidency carrying so few counties.
While Democrats’ shrinking footprint has not prevented them from winning the presidency, it may hinder them from achieving a House majority. Such density aids the construction of districts so overwhelmingly blue that thousands of votes are “wasted” electing candidates sure to win, instead of being cast in competitive races. That helps to explain why even though 50 percent of ballots were cast for Democratic House candidates nationally in 2012, the party’s share of the House next year is only 46 percent, or 201 members.
The difference between Democrats’ share of the 2012 House vote and their share of House seats varies by state. If the two figures were equal in each state, Democrats would gain seats in 23 states and lose seats in 13, for a net total of 219 seats.
Source: David Wasserman/The Cook Political Report; Dave Leip's Atlas of U.S. Presidential Elections