[cnn-photo-caption image= http://i.l.cnn.net/cnn/2008/images/01/31/art.debate3.cnn.jpg caption=" The Republican candidates squared off Wednesday night."]LOS ANGELES (CNN) - The Republican candidates met Wednesday night just days before the make-or-break Super Tuesday primaries with a new national frontrunner – John McCain – and an old rivalry, between the Arizona senator and Mitt Romney, meeting again after a pair of hard-fought campaigns in South Carolina and Florida.
In both contests, McCain scored wins, with former Massachusetts Gov. Romney as runner-up.
Wednesday night's debate, which aired on CNN, was the fourth most-watched primary-season faceoff in cable news history, according to early Nielsen data.
So far this cycle, CNN has broken that record three times, and hosted the four most-watched presidential primary debates in cable news history.
More than 4 million viewers tuned in to see the remaining GOP presidential candidates battle it out on-stage at the Reagan Presidential Library in Simi Valley, California.
Many of those viewers also saw former presidential hopeful Rudy Giuliani officially end his run and endorse rival John McCain shortly before the debate began – immediately followed by an exclusive interview with CNN’s John Roberts.
The Republican presidential rivals crossed swords on stage when Romney accused McCain of deliberately distorting his position on Iraq, and falsely claimed that he endorsed specific timetables for Iraq withdrawal.
“Is it not fair - is it not fair to have the person who's being accused of having a position he doesn't have be the expert on what his position is?” Romney challenged McCain. “How is it that you're the expert on my position, when my position has been very clear?”
McCain responded. “I'm the expert. I'm the expert on this.”
The sparring continued, almost unabated, through most of the forum – which may have allowed underdog candidate Mike Huckabee, who has done well in previous primary season debates, to slip in and score some points.
“The McCain-Romney debate diminished both candidates – they looked like squabbling politicians," said CNN's Bill Schneider. “Who benefits? Huckabee.”
And the shock waves continued on Thursday, as Romney raised the stakes in his battle with McCain, charging that the senator’s comments on his withdrawal position were “reminiscent of the Nixon era, and I don't think I want to see our party go back to that kind of campaigning.”
Both Wednesday night’s Republican debate, and tonight’s Democratic forum at the Kodak Theater in Los Angeles, were co-sponsored by the Los Angeles Times and Politico.com