Sen. Marco Rubio (R-Fla.) endorsed Mitt Romney last night, another in a line of conservatives falling in behind Romney and signaling it’s important to get started on the general election:

As important as the endorsement, which is relatively belated, is the message he sent. A floor fight at the convention would b a “disaster” for the Republicans, he argued. He bluntly stated that the Rick Santorum scheme to take this to the convention would be “a recipe for delivering four more years of Barack Obama.” He added that, after all, Romney has ”earned” the nomination (by garnering a large majority of votes to date).

Moreover, the sense of finality he projected sent the unmistakable signal to the conservative base that the primary race is over. (“It’s evidently increasingly clear that Mitt Romney’s going to be the nominee.”) And he brushed aside the notion that Romney offered an insufficient contrast to President Obama.

It was a solid, on-message appearance. It will no doubt restart the buzz his VP chances.

On that front he was perhaps more equivocal with Sean Hannity than he had previously been. He didn’t say he’d refuse the nomination, only that he wasn’t going to be asked. (Maybe, maybe not.) Rubio is certainly the darling of the conservative base, someone who can articulate domestic and foreign policy principles in an uplifting fashion. But he has never been through a national vetting and has never experienced the nonstop scrutiny of a presidential race. The risk of sending Rubio out too soon in his career is nevertheless a valid reason to pass on the 2012 ticket. It is not as if he is going to disappear from the public eye.

Admirers of Rubio in the Republican Party frequently express the concern that running too soon might “ruin” Rubio as a future leader (i.e. the Sarah Palin flame-out worry) or that his own conservative bona fides might be compromised by running with a candidate who is not the darling of the base.

The latter, I would suggest, is a less-than-compelling reason to forgo the race. Should Rubio help Romney win, he’ll be credited with kicking Obama out. If the ticket fails but he performs well, he may further endear himself to the base (and beyond) as loyal and committed conservative leader in the party and position himself as the favorite for 2016.

For now, however, the drumbeat continues to wrap up the primary. What is the point of prolonging the race — to feed Santorum’s ego or to maximize the GOP’s chances in November? More Republicans, including voters who ultimately control the process, are likely to agree with Rubio and grow impatient with Santorum’s refusal to accept reality.