Transcript for Can Newt Gingrich Beat President Obama?
South Carolina surprise the results walking the Republican race for the White House Newt Gingrich pulling off a huge win beating Mitt Romney by twelve points and when we started looking into the numbers behind the wind look at this -- saying. Electability who could beat President Obama in November was by far the most important thing they were looking for any candidate. And -- that attribute that have been a strong one for Mitt Romney this time going to Gingrich by a wide margin. ABC's Jon -- in Columbia, South Carolina with the results and the reaction tonight. Newt Gingrich it was a smashing. Across the board victory it is up ended the race for the Republican nomination we're gonna make establishment very uncomfortable. We're gonna demand real change in Washington how dirty do it. First debates. -- -- -- The moderator. And South Carolina Republicans he -- -- in November 2 thirds of the debates were important. Most of them went for Gingrich. More than half decided who to vote for the last two days again favoring Gingrich and there was apparently little concern about his divorces. He won decisively among evangelical Christians and women. Gingrich succeeded in portraying Romney -- in Massachusetts moderate trouncing him among those calling themselves very conservative. To date Gingrich stepped up his attacks on Romney as someone just pretends to be conservative of very good salesman. Very very much wants to sell. We as a really weak product and so I think he's been dancing on -- trying to figure out how to find a version Romney. That'll work as for Romney. His support collapsed as he TV basic answers about releasing his tax returns -- so maybe. But you know I don't know how many years all relates today -- finally gave a definitive answer. He will release his 2010 tax return. -- an estimate of -- 2011 tax return on Tuesday we just a -- mistaken and holding off as long as we did it just was a distraction. As the race moves to Florida the Romney campaign will aggressively try to make the case that Gingrich has to -- personal and professional baggage. Characters a big part of leadership -- his vision. Sobriety steadiness. These these are attributes which I think people. Want to see in their candidate while unleashing a barrage of attacks on Gingrich -- -- and on his character. Romney and his allies are trying to demonstrate that Gingrich fails the number one test for many Republicans. Finding the candidate most likely to beat -- -- David. Jon Karl reporting again tonight John thanks to you wanna bring in our senior Washington editor Rick Klein and Rick I wonder why -- now to the big picture here we're have a big fight now in Florida between Romney and Gingrich. The curious with the Obama reelection team would like to see who -- they most want to run against come November. If President Obama got to choose his opponent it would be Newt Gingrich without question even Republicans are starting to worry that Gingrich could drag down his fellow Republican candidates if he's the presidential nominee so Democrats are still training all of their fire on Mitt Romney which actually could boost Gingrich's chances in Florida and beyond. But the lesson here David in the last couple days is that when it comes to Newt Gingrich be careful what you wish for. All right all eyes on Florida the weeks ahead -- tonight thanks to you and a reminder Diane Sawyer and George Stephanopoulos will anchor live coverage. A president Obama's State of the Union Address and the Republican response it's Tuesday night. -- in 9 o'clock eastern right here on ABC.
This transcript has been automatically generated and may not be 100% accurate.