Before the election, I highlighted a report arguing that Republican control of state legislatures would end up earning them about 11 seats because of redistricting. The fact that the House total barely budged in a very good year for Democrats nationally — and in which House Democrats won the popular vote — suggests that this probably played a role.
This is especially clear if you take a look at the share of House seats won by Democrats in states where Republican-controlled legislatures redistricted in 2011 and 2012, and compare that to the share of the vote President Obama won.
Utah gave a quarter of its vote to Obama and a quarter of its House seats to Democrats, and New Hampshire sent two Democrats to the House despite Obama's only having a six-point margin there. But otherwise, these states all sent far fewer Democrats to Congress than the Obama votes would suggest.
Florida, Wisconsin, Ohio, Michigan, Virginia and Pennsylvania were the worst offenders. In each case, only a small number of seats from each state went to Democrats despite the fact that Obama won all of them. In Virginia, for instance, 27 percent of seats went to Democrats, while Obama got 52 percent of the vote. In Pennsylvania, 28 percent of seats went to Democrats, and Obama won 53 percent.
Accomplishing this required, as Dave Weigel noted Wednesday, truly bizarre district shapes. The following chart shows Pennsylvania, a state where Obama beat Mitt Romney by 6 points in the two-party vote.
All the Democrats in Pittsburgh and Philadelphia were put into a mere four seats, and the other 14 were left for Republicans.
This isn't as true for Democratic-controlled redistricting, and not just because Democrats ran redistricting in only six states. Democrats are just worse at gerrymandering when they get the chance. While Democrats outperformed their presidential vote in House races in Rhode Island, Maryland, Massachusetts and Illinois, they underperformed in Arkansas and West Virginia.
This suggests that it's going to be tough for Democrats to make big gains in the House until 2022, when the districts are drawn again following the Census. And for that to happen, they'd have to do quite well in the 2020 state legislature elections.