And not for the first time this week, either.  Tea Party sensation Senator Marco Rubio has remained officially neutral in the Republican presidential primary race, but that may end up changing, in practice if not in declaration.  Two days in a row, Rubio has come to the defense of Mitt Romney, scolding Newt Gingrich for misrepresenting Romney while campaigning in Florida, this time on immigration (via the Boss Emeritus):

 Sen. Marco Rubio scolded Newt Gingrich’s presidential campaign over a Spanish-language radio ad that accuses rival Mitt Romney of being “anti-immigrant.”

“This kind of language is more than just unfortunate. It’s inaccurate, inflammatory, and doesn’t belong in this campaign,” Rubio told The Miami Herald when asked about the ad.

“The truth is that neither of these two men is anti-immigrant,” Rubio said. “Both are pro-legal immigration and both have positive messages that play well in the Hispanic community.”

Rubio’s sharp rebuke comes a day after he subtly corrected Gingrich for comparing Romney to former Florida Gov. Charlie Crist, branded by conservatives as a turncoat who left the party before Rubio beat him in 2010.

Subtly?  Not exactly.  Rubio slammed the comparison, reminding Florida voters that Romney campaigned for Rubio against Crist in 2010, and was “one of the first national Republican leaders to endorse me.”  The statement didn’t name Gingrich, but the message was clear — Romney made a difference on behalf of Rubio, not Crist, and apparently did more than Gingrich in that effort.  The only thing missing from that statement was a mention of DeDe Scozzafava.

Rubio’s opinion will make a great deal of difference to conservatives in the Sunshine State, which Rubio obviously knows.  He’s taking care not to tip his hand, especially since either one of the two front-runners might want Rubio as a running mate (which I believe would be a mistake for Rubio, but that’s a subject for another post).  However, having to come to Romney’s defense twice to answer attacks from Gingrich — and especially reminding voters which of the two men took Rubio’s side earliest in the Senate race — is bound to have an impact on how conservative Florida voters perceive Rubio’s position.  And given Rubio’s popularity nationally among Tea Party activists and grassroots conservatives, these defenses could have an impact well beyond Florida.

Update: Newt Gingrich’s team has now agreed to pull the ad after more than a dozen Hispanic politicians in Florida joined Rubio in demanding it:

In the wake of Sen. Marco Rubio’s denunciation of Newt Gingrich’s ad calling Mitt Romney ‘anti-immigrant,’ the Romney campaign’s Hispanic leadership team — headlined by former Sen. Mel Martinez — is demanding that Gingrich pull down the radio spot.

But Gingrich already plans to do it.

“We respect Senator Rubio tremendously and will remove the ad from the rotation. We will replace it with a positive message that will continue to focus on drawing contrast between our clear vision on the issues important to the hispanic community and our oponnents lack thereof,” Gingrich’s Florida campaign chairman, Jose Mallea, said.

Looks like Gingrich doesn’t want to force Rubio into choosing sides.