Republicans' gerrymandering could help Democrats
The tea party wave of 2010 cost the Democrats the House, and then Republicans gerrymandered congressional districts to remain in power. But drawing districts with the intention of helping your party is an act of statistical modeling, and all models have assumptions, biases and flaws. A midterm election with an unpopular Republican president will reveal some of the flaws in the Republican Party's gerrymandering. The redrawn lines may even benefit Democrats.
The House gerrymander that Democrats complain about is mostly a phenomenon in five states -- Michigan, North Carolina, Ohio, Pennsylvania and Virginia. President Barack Obama carried all five states in 2008, yet after the 2010 Census, Republicans in those states drew district maps that were very favorable to their party. Those five states have a combined 73 seats in the House -- currently 52 Republicans and 21 Democrats. Those 73 seats are all held by the party favored to hold those districts, according to the Cook Partisan Voting Index.