Rasmussen’s latest poll in Iowa gives Newt Gingrich a big claim to legitimacy in the Republican nomination fight, but it also is pretty good news for Mitt Romney as well.  Among likely caucus-goers, Gingrich now leads Romney 32/19, with Herman Cain dropping more than half of his previous support:

The latest Rasmussen Reports national telephone survey of Likely Iowa Republican caucus-goers shows Gingrich with 32% followed by former Massachusetts Governor Mitt Romney at 19%. Georgia businessman Herman Cain, who led in Iowa last month, drops to third with 13% of the vote. Texas Congressman Ron Paul draws 10% of the vote in Iowa, while Texas Governor Rick Perry and Minnesota Congresswoman Michele Bachmann each grab six percent (6%).

Former Pennsylvania Senator Rick Santorum draws support from five percent (5%) of caucus-goers while former Utah Governor Jon Huntsman picks up two percent (2%). Only one percent (1%) would prefer some other candidate and six percent (6%) more are undecided.

This is the first primary survey conducted entirely after last week’s GOP debate on foreign policy. Cain also recently fumbled a response to the administration’s actions in Libya.

This comes from a sample of 700 respondents, which is larger than the Bloomberg survey released this week showing a four-way tie in Iowa.  This survey took place more recently than the Bloomberg poll as well, incorporating the Saturday debate on foreign policy, in which Cain struggled.  As far as the Ron Paul surge Bloomberg noted, it seems to have bypassed Rasmussen’s sample.  In fact, while Paul continues to hold onto about 10% of the caucus goers in Iowa, he’s not likely to get much more:

Ron Paul, while placing fourth overall, is also the candidate Iowa voters least want to see win the nomination. Eighteen percent (18%) hold name Paul as the least favorite candidate followed closely by Bachmann at 15%. Thirteen percent (13%) don’t want to see Romney or Huntsman grab the nomination, while 11% would like to see Cain miss the nod. Only eight percent (8%) name Gingrich as the candidate they least want to see win.

Essentially, Rasmussen reports that Cain and Gingrich have changed places since their October poll, while Romney and Paul have remained constant.  That’s good news for Romney, who isn’t playing for a win in Iowa.  A strong second-place finish will suit him well as the primaries roll into New Hampshire, and then Michigan and Nevada.  He needs to avoid falling below third place, but even that wouldn’t be a total disaster for Romney in a state he wasn’t expected to win.

In the crosstabs, Gingrich is winning across most of the demos now.  He leads Romney by double digits among men and women, wins every age and income demo, and leads both Republicans and independents.  Romney only bests Gingrich among ideological “others,” those who do not identify as “very conservative” or “somewhat conservative.”  Interestingly, Gingrich leads among Tea Party adherents by a wide margin, 43% to 17% for Cain and only 9% for Romney.  Gingrich leads most of the religious demos, too, with 33% of evangelicals (Cain second at 14%), 31% of Protestants (Romney close at 28%), and Catholics (39% to Romney’s 21%).  Only among “others” does Gingrich trail, 22%, to 24% for … Ron Paul.

Of course, several candidates have grabbed this kind of momentum in this race, only to come up empty within a few weeks.  Can Gingrich maintain this momentum?   As the media and other candidates step up their scrutiny of the former Speaker, we will certainly find out.  One thing is almost certain: unlike the previous bubble candidates, it won’t be a debate that trips Gingrich.