Michael Barone has a serious article today suggesting that the off year vote for the House is an excellent indicator of how the President election might turn out two years later.  GOP gains in 2002, signaled Bush's victory in 2004. Big Democratic gains in 2006 were spot on with 2008 results. In 2010, the GOP won 53% of the national vote for the U.S House, to 46% for the Democrats.  

Barone has done the math, in anticipation of his new edition of the Almanac of American Politics, and also found that the GOP carried the overall House vote in 35 states in 2010.  Those 35 states account for 351 Electoral College votes in the 2012 elections.  The 15 states where the Democrats won the overall House vote in 2010 plus D. C, accounted for 187.  Barack Obama won 9 states that George Bush carried in 2004: Indiana, North Carolina, Virginia, Ohio, Florida, Iowa, Nevada, New Mexico, and Colorado.  He held all of the Kerry states from 2004.  In the 2010 midterms, the GOP won the overall House vote in 8 of the 9 states Obama moved from the Bush column -- all but New Mexico.  

But the GOP did more than that.  They also won the House vote in 5 states that Kerry had carried in 2004: Wisconsin, Michigan, Pennsylvania, New Hampshire and New Jersey.   Very few analysts think New Jersey is within reach for the GOP Presidential candidate in 2012, but Chris  Christie won the Governor's race in 2009, and the GOP won the U.S. House vote in 2010.  Of course, the mix of voters will be different in 2012 than in 2010, favoring the Democrats.  The minority voter share of the electorate may be 4 or 5% higher in 2012 than it was in 2010. 

But the good news for the GOP is that a path to 270 Electoral votes is clear, at a time when Obama's approval ratings keep dropping (now below 46%), when even Democratic leaning pollsters such as PPP say his numbers are the worst in over a year, when Mitt Romney runs even with Obama nationally and in key tossup states,  The GOP's fate in 2012 does not depend  solely on holding Bush states from 2004. This time, several Kerry states from 2004 will be in play. 

The Senate

The GOP has high hopes for taking control of the Senate in 2012.  With 47 seats, the GOP needs to win 4 to take control, or 3 if Obama is defeated and just for fun, say Vice President Rubio casts the tiebreaker.  The retirement of Kent Conrad has put North Dakota in play (a likely GOP pickup), and  Herb Kohl's retirement in Wisconsin and Jim Webb's in Virginia  have made these seats  tossup races.  Jeff Bingaman's retirement in New Mexico has given the GOP a shot at picking up this seat, though the Democrats are slightly favored to retain it.  Democrats elected in the wave year in 2006 face serious challenges in Montana (Jon Tester), Missouri (Claire McCaskill) , and Ohio (the very liberal Sherrod Brown).  Ben Nelson in Nebraska,  best known for his Cornhusker kickback that secured his vote for the very unpopular ObamaCare bill, trails in his race for re-election.  Bill Nelson in Florida, and Debbie Stabenow in Michigan  face more serious challengers than they did in 2006. 

The GOP will have to defend Scott Brown's seat in Massachusetts (though his high approval ratings make him the favorite), and the seat now held by appointed GOP Senator Dean Heller in Nevada, who is in a close race with Congresswoman Shelley Berkley.  GOP incumbents Olympia Snowe in Maine, and Richard Lugar in Indiana face tea party challengers in their primaries.  Snowe  seems in good shape in the primary race and if she is the nominee, should be an easy general election winner.  Lugar may be in more trouble in the primary, though in GOP leaning Indiana, either Lugar or his challenger, Richard Mourdock could probably hold the seat. 

There is also a wild card: if the GOP runs the table and wins the White House and takes control of the Senate, I fully expect that Democrat Joe Manchin of West Virginia will consider switching parties.  Manchin has a more conservative voting record than several Republicans in the House and Senate. Jim Jeffords of Vermont switched to the Democrats to get higher milk prices.   Manchin has more serious concerns such as the EPA's war on coal companies and miners  in his state.

Most people are focused on the Senate, but the battle for control of the House will be hard fought in 2012 for several reasons. A shift of 24 seats would give the Democrats control. With redistricting, many incumbents will be running in new districts, where they are less familiar to some of the voters.  In Illinois, State Assembly Speaker Mike Madigan's new districts  laid waste to the GOP's gains in 2010.   Illinois lost a seat (Judy Biggert's district disappeared).   Madigan "unpacked" several black majority districts, adding suburban Republican voters and moving them from 85-90% Democratic, to perhaps 70% Democratic.  Other Democrat-held seats -- Mike Quigley, Dan Lipinski,  Jan Schakowsky and Jerry Çostello -- also became  less Democratic by adding GOP leaning voters, but remained safe for the Democrats  (so long as the incumbents keep running).  By taking GOP-leaning voters from several suburban districts, and adding Latino voters to them, several GOP held seats won narrowly in 2010 are now less favorable for the incumbents in 2012, some of whom now live outside the district that elected them. Sean Trende summarizes Madigan's handiwork:

The Madigan plan is being challenged in Court, though I think it is likely to survive.  There are as many Latinos as African Americans in Illinois, but there are 3 black districts, and only one Latino majority district ( a gem of gerrymandering), and in that one, a Puerto Rican is the House member. Illinois' Latino population is overwhelmingly Mexican American. When push comes come to shove, the Democrats will always favor blacks over Latinos, unions over companies, taxpayers and non-union workers, trial lawyers over companies and doctors, environmentalists over companies and consumers.  Some may discern a pattern -- if  "groups" fund Democratic candidates, or vote heavily for them, they get the goodies, national interest be damned.

In Texas and Florida, the Republicans in the state legislature have created or are likely to create new Latino majority districts, which may help those plans survive. In North Carolina, a Madigan like plan has shifted several marginal Democratic leaning districts to marginal GOP leaning districts. On balance, the national redistricting may prove a wash for both parties.