Newt Gingrich won South Carolina going away. Mitt Romney is now in for a dog fight in Florida and faces a long primary battle. Gingrich won on the strength of two stunning debate performances and by convincing voters he was to Romney’s right. With the collapse of the other not-Romney candidates, Gingrich took a big step toward consolidating that part of the electorate. It is a mistake to say that Romney’s support collapsed in South Carolina; Rather, Gingrich is now getting most everyone else.

Rick Santorum is projected to come in third, keeping his campaign alive for Florida. He, however, has not been able to turn his showing (now a win) in Iowa into real momentum and is at risk of seeing this become a two-man race. If he can’t catch either Romney or Gingrich in Florida his campaign becomes problematic.

As some suspected, we are in for a state-by-state battle that will be played out for weeks and perhaps months. Romney has the advantage in organization and a lead in money (which may narrow considerably). But he will now have to turn his attention away from a general election face-off with President Obama and take it to Gingrich. We saw the beginning of that today with a Romney team e-mail wishing Gingrich a happy 15th anniversary on his reprimand by the House of Representatives, which the Romney news clips point out was not partisan and was not led by Rep. Nancy Pelosi (D-Calif.), as Gingrich has claimed. You’re going to see an avalanche of attacks plus a feistier Romney willing to defend his Bain experience against the opportunistic Gingrich.

I’ll have more to say tomorrow about the potential for a new candidate in the race. But from the point of view of Republicans who understand just how toxic Gingrich is beyond the GOP base, the race tonight became “anybody but Newt.”

Update: Mitt Romney’s concession speech was as strong a pivot as he could have hoped to pull off. Tonight saw a more fired up Romney. (“I’m passionate about defending economic liberty!”) He emphasized this is the beginning of a long race. But the substance of his speech focused on casting Newt Gingrich in the role of the Washington legislator/attacker of free enterprise and himself in the role of job creator/defender of capitalism. He declared again that President Obama never ran a business or a state, and so the GOP cannot be led by someone who never ran a business or led a state. He pressed on, asserting that Republicans can’t win with a candidate who joined the left in an assault on free enterprise.

And then his most quotable line: “Those who pick up the weapons of the left today will find them turned against us tomorrow.” In sum, he is telling the broad cross-section of Republican voters that Gingrich will be their ruin and he, Romney, will step up to the plate in defending conservative economic principles.