Mitt Romney delivered a blowout in Florida today. He’s clobbered Newt Gingrich in three of the four states so far, and proven that Gingrich is terribly vulnerable to attacks. Meanwhile, Rick Santorum finished a weak third, and Ron Paul, who mostly skipped Florida, ended up a distant fourth.

At this point, Romney essentially has the nomination wrapped up. Yes, people will point out that only a very small portion of delegates has been selected, but most of these contests are usually long over when the winner finally hits the mark that technically clinches it. Realistically, only some sort of external and utterly unexpected event could derail Romney now.

That doesn’t mean, however, that the fighting is over. While Santorum will probably drop out soon ( it’s difficult to see any reason for him to remain in the contest), Gingrich will likely fight on until (at least) Super Tuesday, and, of course, Paul will presumably fight through to the convention. It’s certainly possible that Gingrich, or even Paul, could still win a handful of states; in particular, as Steve Kornacki has been saying, it’s still not clear whether Romney will win in the traditional (that is, non-Florida) South.

What Romney probably does get with tonight’s big win is a bit of a reprieve. He can, if he chooses, go back to bashing President Obama instead of fighting with other Republicans.

We’ll see, however, if there isn’t some sort of weird equilibrium in which Gingrich’s popularity rises every time he’s out of it and people stop reminding Republican voters about all the reasons they should oppose him, and then sinks rapidly as soon as they do. One thing to keep an eye on: Even though there’s only one debate scheduled in the month of February, there are two in the first few days of March leading up to Super Tuesday.

Assuming, that is, that party leaders can’t convince Gingrich to either give up the fight, or, at least, run a campaign targeting only Obama. It’s certainly in the party’s interest to try that now. Can they succeed? I have no idea; perhaps the only one who really knows is Gingrich donor Sheldon Adelson. After all, it’s apparently up to him whether Gingrich will have enough money to pretend that he’s running a real campaign for the next month.

So: Romney wins big, and makes it clear that he will be the nominee, but we don’t know yet how hard he’ll have to fight over the next five weeks. 

More opinions on the Florida primary

Rogers: Romney needs to heal GOP wounds

Stromberg: Will Santorum surge?

Dionne: Who resisted Romney?

Robinson: The battle’s not over

Rubin’s Gingrich’s graceless speech