December’s Field Poll on the 2012 presidential contest, which shows President Obama leading Mitt Romney by 10 points and Newt Gingrich by 20 points, also gives us a few clues about the outcome of next year’s congressional races.

The survey suggests that if Romney heads the GOP ticket, Republicans might do all right in the congressional contests; if Gingrich heads the ticket, they could take a bath.

That is because federal races have now become nationalized, and California voters may be less likely to split their tickets between president and congress than they were in the past.  California had very few hotly contested congressional races under the gerrymandered plan in effect for the past decade.  The 11th Congressional District that covered parts of the East Bay and San Joaquin County was the only one to change hands; Democratic Rep. Jerry McNerney won it by ousting a Republican incumbent in 2006.

Republicans made a major effort to win back the seat in 2008, but that was a presidential election year and then Sen. Obama swept California.  He won the 11th CD by a 55 to 45 percent margin.  And the result for the congressional race was exactly the same; McNerney won re-election with 55 percent.  A look at the numbers in the four county district shows there was no ticket splitting.

So it is worthwhile to look at how Romney and Gingrich are running against Obama in the areas likely to see hot congressional races in 2012.  With the new congressional districts drawn by the Citizens Redistricting Commission, there could be as many as a dozen contested races in 2012.  Let’s look at six of them:

CD 3, Sacramento Valley: Republicans may well target Rep. John Garamendi with Colusa County Supervisor Kim Vann.  Carly Fiorina narrowly carried this CD over Sen. Barbara Boxer in 2010, but Obama won it with 55 percent in 2008.

CD 7, Sacramento suburbs: Rep. Dan Lungren against Democrat Ali Bera will be a hot race. Fiorina carried the district but Obama got 51 percent here.

CD 21, Central Valley-Bakersfield: A close contest is likely between Democrat Sen. Michael Rubio and GOP Assemblyman David Valadeo.  Fiorina carried district handily but Obama won it with 52 percent.

CD 24, Central Coast: Democratic Rep. Lois Capps probably will face former GOP Lt. Gov. Abel Maldonado.  Fiorina won the seat narrowly but Obama got 56 percent.

CD 26, Ventura: This could be an open seat if Rep. Eldon Gallagly retires.  As with CD 24, Fiorina narrowly carried it but Obama won it with 56 percent.

CD 52, San Diego: Democrats are looking at possibly targeting Rep. Brian Bilbray in a GOP leaning district.  Fiorina won it easily but Obama carried it with 55 percent.

The important point is not whether Obama carries California, he will unless there is a Reagan-like national GOP landslide. But how closely he wins the state could well determine whether Democrats or Republicans prevail in as many as 12 possible toss-up House contests.  Given that California has the nation’s largest congressional delegation, an Obama blowout like we saw in 2008 – he carried the state by 24 points – could determine whether Democrats make huge gains here and possibly win back control of the US House.

The Field Poll finds Romney getting 40 percent while Obama is at 50 percent; that is close to the numbers in the Boxer-Fiorina race, and the poll also shows Romney beating Obama in the Central Valley, in San Diego and the Inland Empire, and running well along the coast. This is where most of the hot congressional contests will occur.

On the other hand, Gingrich receives only 35 percent – about the GOP base vote – while Obama is getting 55 percent – the Democratic vote plus independents.  And Gingrich loses most areas where toss-up congressional contests are likely.

So the margin in the presidential contest, while not relevant in awarding Electoral Votes, could be crucial to whether the GOP holds its own in the congressional races, or whether Democrats can score the huge gains in congress they did not score under the old gerrymandered plan.