On the same day last November that President Obama was reelected by a solid margin, his party’s candidates for the House received about 1.5 million more votes collectively than the GOP’s candidates. And yet when the new Congress convened, Republicans still enjoyed a solid majority in the lower chamber, with 235 seats.
The most popular explanation for this disparity involves gerrymandering—when one party uses its control of state government to redraw congressional district lines in a way that gives its candidates an electoral edge. Gerrymandering has been around for a while—it takes its name from 19th-century Massachusetts Governor, Elbridge Gerry—and it’s been practiced by both parties at the congressional and state legislative levels.
But thanks to the 2010 midterm wave that gave them control of governorship and legislatures in a bunch of big states, Republicans were better positioned to put it to use after the most recent census. And sure enough, when you look at the results from states like Pennsylvania and Ohio, where Mitt Romney lost the statewide vote while Republicans won the overwhelming majority of House seats, the whiff of gerrymandering was strong in 2012.
But gerrymandering isn’t the whole story behind the GOP’s House majority—and it isn't even the prime driver of that. There’s actually a more basic explanation: More than ever, the Democratic Party’s core voters live in tightly-packed metropolitan areas, while the GOP’s core voters are more broadly dispersed across any given state.
Democrats have traditionally fared well in urban areas, but the trend is accelerating. As David Wasserman of the Cook Political Report noted recently, in his victory over Romney, Obama won fewer than 700 counties nationally; compare that to 1988, when Michael Dukakis carried more than 800, despite suffering a landslide defeat. Consequently, the imbalance we saw in the most recent House elections is basically unavoidable. Democratic House candidates can rack up massive majorities—sometimes more than 80% of the vote—in metropolitan areas, while Republicans carry more districts statewide with a lower share of the vote (say, 55% or 60%).
I recently discussed all of this at the 92nd Street Y here in New York, as part of their American Conversation series.