How much did Monday’s debate move the needle in South Carolina?  This much, and it’s not as much at the expense of Mitt Romney as it is the rest of the field:

Former House Speaker Newt Gingrich has now surged ahead of Mitt Romney in the final Rasmussen Reports survey of the South Carolina Republican Primary race with the vote just two days away.

The latest telephone survey of Likely GOP Primary Voters in the state finds Gingrich with 33% support to Romney’s 31%. Two days ago, before the last debate, it was Romney by 14 percentage points.

Texas Congressman Ron Paul now runs third with 15% of the vote, followed by former U.S. Senator Rick Santorum at 11%. Paul’s support is steady while Santorum’s support has dropped five points since Monday.  At the beginning of the month, just after Santorum’s strong showing in the Iowa caucuses, he ran second to Romney with 24% of the vote.

Rick Perry’s support came in at 2% in the survey taken yesterday, before his withdrawal today.  Perry endorsed Gingrich on the way out of the race, but that seems to have been more of an acknowledgment than a gift.

A week ago, Romney had a 7-point lead, and two days ago it was 14 points in the Rasmussen series.  This represents a huge shift, perhaps not too surprising after Gingrich’s splendid debate performance on Monday.  However, with his ex-wife dishing on his affair with his present wife today and tonight, Gingrich might have some difficulty holding onto this support.  His jump came among the “very conservative” bloc, which now favors Newt 42/22 over Romney while the “somewhat conservatives” edge towards Romney by three, 36/33.  Gingrich also cleaned up among evangelicals in this latest poll, 37/21, and got a little closer to Romney among women, now only trailing by nine, 27/36.  Most of these demos will not appreciate the dirty laundry airing at the moment in South Carolina, and if this is the first time that many of these voters have heard these stories (as contrasted to those of us who are immersed in politics), then Gingrich’s boomlet could be very short-lived.

The NBC/Marist poll taken Monday and Tuesday also shows momentum swinging to Gingrich, although with Romney still in the lead:

As the Republican presidential candidates crisscross the Palmetto State in the days leading up to Saturday’s South Carolina primary, Mitt Romney leads Newt Gingrich, 34% to 24%, among likely Republican primary voters including those who are undecided yet leaning toward a candidate based on interviews conducted on Monday and Tuesday.

Debates matter.  Romney’s Monday lead of 15 percentage points over his closest competitor, Newt Gingrich, narrowed to 5 percentage points on Tuesday following Monday night’s debate.

Marist highlights the key findings, which have Romney leading Gingrich among Republicans by eight points, and thirteen points among independents (Paul comes in second, two points behind Romney).  Just as in the Rasmussen poll, self-identified “very conservative” voters go for Gingrich by double digits, 33/23 with Santorum getting 22% for a close third.  Tea Party support shifted in the two day poll from 35/27 Romney to 34/27 Gingrich for a 31/31 tie overall.  Evangelicals also flipped overnight, 36/22 for Romney on Monday and 37/22 Gingrich on Tuesday, while Santorum maintained third place at 19% and 18% respectively.

Again, if evangelicals and Tea Party supporters are hearing about the dirty laundry of Gingrich’s personal baggage for the first time, those numbers may flip again and leave Gingrich in position to finish behind Romney.  If this is old news in South Carolina, it won’t make much difference at all.  We may not have time to get good polling on that question before Saturday’s vote, either.