Obama may be president. Democrats may keep the Senate. But the House isn’t going anywhere.

But let’s focus on Ohio. Right now, Obama is winning the state, and Democrats are saying things like “it appears he’s going to run a little bit ahead in Ohio than he does nationally.” In 2008, Obama carried the state and boosted the whole Democratic ticket—10 of Ohio’s 18 members of Congress wore the blue jerseys. In 2010, Republicans snatched back five seats. The census took away two of Ohio’s districts, but Republicans redrew the map to make it functionally impossible for Democrats to win back turf.

This (via the Cook Political Report) used to be Ohio’s 1st Congressional District:

In 2008, Obama won this by 31,128 votes and swept Steve Chabot out of office. In 2010, Chabot won a comeback bid by 11,098 votes. The overall Chabot vote slipped from to 140,469 in 2008 to 103,770 in 2010. But he’s safe now. The new district looks like this:

The old district forced Chabot to compete in Cincinnati while winning Republicans in neighboring Butler County. But the new district excises Cincinnati—that’s the jagged hole—and brings in a chunk of Republican heaven, Warren County. It’s one of 11 districts that favor Republicans, and nine of them strongly favor Republicans. Obama may win the state with 51 percent of the vote while Democrats win 31 percent of the House seats.

Most of the GOP-run states now look like this. If you want a general idea of where blacks, Hispanics, and liberal whites don’t live, load a new district map of North Carolina or Pennsylvania or Michigan. If you’re worried about partisanship, it’s time to upgrade to panic. Anyone who wins a new, safe seat can safely ignore whichever kook or LaRouche cultist runs against him. He only has to worry about staying pure enough to win his primaries. In a long look at the new maps, Robert Draper talks to Rep. Blake Farenthold, who’d be a fluke one-termer if the Texas legislature didn’t shore up his seat. “This [new] district is a much stronger Republican district,” Farenthold says to Draper. “You say the same thing, but you use different words. Immigration would be an issue … you’ll be a little softer about how you talk about it in a swing district than in a harder-core Republican district.” Any Democrat in Ohio could say the same thing.

But from the Nancy Pelosi algebraic perspective, as pure politics, the new maps mean that it’s easier for a Democrat to win the White House than for his party to take the House. For generations, the exact opposite was true. The old New Deal coalition, from 1933 to 1995, gave Democrats control of the House for 56 of 62 years. The South would produce an army of Democrats—conservative, but good enough for the speakership—no matter who won the election. As late as 1984, Georgia voters could go to the polls, give Ronald Reagan a 20-point landslide, and give Democrats eight of their 10 congressional districts. “At the time,” former Reagan (and Nixon) strategist Roger Stone told me in an email, “we attributed our small gains to the districting maps—and, with party ID still near parity, the desire of voters for ‘balance.’ ”

Since then the Electoral College has shifted toward the Democrats. Obama has given up the old Democratic strongholds of the Deep South, trading them for the Hispanic-heavy Southwest, the Midwest, the Mid-Atlantic, and New England. The more diverse the state, the better the national Democrat does. Most of the country’s getting more diverse. It’s been decades since the GOP was able to compete for California or Illinois or New York, all of them won by Reagan and Nixon. It’s been 24 years since a Republican won Pennsylvania.

Maybe a swing state’s gotten impossibly tough for a Republican to carry. Carve it up right, and you can put the demographically troublesome voters in the districts where they can do the least damage to your party. “We'd have to see an amazing landslide in order for these districts to flip,” McHenry says. “If there was a big coattail effect, that would mean that the people who drew the districts didn't do very good jobs.”