It wasn’t just redistricting that gave Republicans their House majority
I estimated which of their 50 states had more votes cast for Barack Obama and which had more votes cast for Mitt Romney. My count is Romney 29, Obama 21. So their plan would have produced a Romney presidency. Now obviously the campaign would have been conducted differently if the Electoral College worked that way. But my point remains solid: in an election in which Obvama won the popular vote 51%-47%, a politically neutral division of the nation into 50 equal-population states would have given Romney 58% of the electoral votes and Obama 42%. Equal-population districts work against the Obama Democratic coalition.
This effect was visible as well in elections to the House, which have equal-population districts within each state. Republicans won 234 seats in the House and Democrats 201. Mitt Romney appears to have won (I’m waiting on final counts) 228 House districts and Obama 207.
Interested readers with time on their hands might want to actually calculate the vote in each of these districts, and my estimates may be wrong in a couple of cases. But if I’m anywhere close to right, Romney carried a majority of these equal-population states.