Rivals press Romney to release tax returns

MATT LAUER, co-host: Now to presidential politics. GOP front-runner Mitt Romney faced some pretty tough questions from his rivals last night during a debate in South Carolina including a direct challenge to release his income tax returns . NBC 's Peter Alexander is in Florence , South Carolina . Peter , good morning.

PETER ALEXANDER reporting: Matt, good morning to you. Remarkably this was the 16th debate of this election cycle. Describe it as aggressive, combative, the language used by the South Carolina chair of the Republican Party was the gloves are off. This is the big brawl. And that was exactly the case. The prime target again: Mitt Romney .

Offscreen Voice: Former Massachusetts Governor Mitt Romney .

ALEXANDER: Front-runner Mitt Romney on the defensive from the very start, responding to tough questions about his time at Bain Capital .

Former Representative NEWT GINGRICH: But there was a pattern in some companies, a handful of them, of leaving them with enormous debt and then within a year or two or three having them go broke. I think that is something he ought to answer.

Former Governor MITT ROMNEY: Some of the businesses we invested in weren't successful and lost jobs. And I 'm very proud of the fact that we learned from the experience. We invested in well over 100 different businesses.

ALEXANDER: In perhaps the most heated exchange of the night Rick Santorum challenged Romney over a pro- Romney ad that criticized Santorum for supporting voting rights for felons who've already served their time.

Former Senator RICK SANTORUM: Should they be given the right to vote ?

Gov. ROMNEY: First of all, as you know, the PACs that run ads on various candidates, as we unfortunately know, in this...

Sen. SANTORUM: I'm looking for a question -- an answer to the question first.

Gov. ROMNEY: We have plenty of time. I'll get there. I'll do it in the order I want to do.

ALEXANDER: The fight over so-called super PAC ads intensified.

Sen. SANTORUM: If I had something the super PAC that was supporting me that was inaccurate I would go out and say stop it.

Rep. GINGRICH: Well, this is typical of what both Senator Santorum and I've complained about with Governor Romney 's super PAC , over which he apparently has no influence which makes you wonder how much influence he'd have if he were president.

Gov. ROMNEY: We all would like to have super PACs to disappear, to tell you the truth. But you know what, this campaign isn't about ads, it's about issues.

ALEXANDER: Rick Perry bluntly called on Romney to release his tax returns .

Governor RICK PERRY: We cannot fire our nominee in September. We need to know now.

ALEXANDER: When pressed, Romney , who made millions in the private sector, seemed to open the door on releasing his returns, but was careful not to commit.

Gov. ROMNEY: We're showing a lot of exposure at this point and if I become our nominee, I'm -- and what's happened in history is people have released them in about April of the coming year and that's probably what I'd do.

ALEXANDER: When one question suggested Gingrich was trying to belittle the poor, the crowd booed, then responded to his answer with a standing ovation.

Rep. GINGRICH: And if that makes liberals unhappy I'm going to continue to find ways to help poor people learn how to get a job, learn how to get a better job and learn someday to own the job.

ALEXANDER: And Mitt Romney 's Republican rivals now have just four more days to try to knock him off message. There is also one more debate, all of it leading up to this Saturday's first in the South primary. Matt: