Republican front-runner Mitt Romney is looking for a sweep in three Republican primaries on Tuesday, hoping to tighten his grasp in the contest to decide who will challenge President Obama in the November general election.
However, his main rival Rick Santorum, who is facing long odds in the next set of primaries and beyond, urged Republican voters Monday to help him battle Romney all the way to the convention if that's what it takes to "get the best candidate."
The former Pennsylvania senator was defiant, as party elders put not-so-subtle pressure on him to bow out.
Though polls show Romney poised for another strong showing in the upcoming contests -- in Wisconsin, Maryland and the District of Columbia on Tuesday -- Santorum vowed to carry on regardless of the outcome. Speaking to reporters in Wisconsin, he said: "The longer it goes the better it is for the party."
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Santorum further claimed it would be "positive" for the GOP to battle it out at the Tampa convention, just two months before the general election. "I think it would be a fascinating display of open democracy, and I think it would be an energizing thing for our party," Santorum said.
However, Romney is talking more and more like the nominee, as he closes in on the 1,144 delegates needed to clinch the nomination.
According to the Associated Press tally, Romney hit the halfway point on Monday when a Tennessee GOP decision bumped him up to 572. The contests on Tuesday will put him well past that mark -- he could even sweep the day, with polls showing him ahead in Wisconsin and Maryland and with Santorum absent from the ballot in the District of Columbia.
Romney, recognizing the odds, abandoned his typically cautious tone Sunday evening and referred to himself as the likely nominee when discussing Democratic efforts to target the Republican candidate.
"This president can't run on his record. And so he's going to try in every way he can to divert to some other kind of attack and try to have people disqualify our nominee, which will probably be me," Romney said.
Indeed, top Obama administration officials -- including Vice President Biden and Secretary of State Hillary Clinton -- over the weekend trained their criticism on Romney, particularly his foreign policy positions.
Top Republican leaders have endorsed Romney over the past week, including Florida Sen. Marco Rubio and Wisconsin Rep. Paul Ryan. And Senate Republican Leader Mitch McConnell, while not endorsing anyone, said in an interview Sunday that Romney is the likely choice so "it's time to turn our attention to the fall campaign" and make the case against Obama.
According to the latest Associated Press count, Romney has 572 delegates. Santorum has 273, Gingrich has 135 and Paul has 50.
If Romney's rivals choose to make the GOP nomination a fight to the finish, after Tuesday's contests they will have to wait until contests in late April -- and possibly early May -- to have a shot at eroding his lead.
Santorum is eyeing his home state of Pennsylvania, which holds its primary along with four other states on April 24, for his next big chance. The former Pennsylvania senator on Monday said he "absolutely" will win Pennsylvania. He said he might even eke out an "upset" in Wisconsin.
But the other April 24 contests are being held in the kind of New England and East Coast states, like New York and Connecticut, seen to be favorable territory for the former Massachusetts governor.
Santorum, on "Fox News Sunday," said he was looking ahead to May -- when conservative states like West Virginia and Texas are voting.
Santorum said he would keep going no matter how he performs in Wisconsin, which is seen as the battleground this Tuesday.
Speaking in Mishicot, Wis., Santorum suggested the show of financial strength on Romney's part is another sign the race should go on.
"Why is he spending $4 million in Wisconsin if the race is over -- if it's over and you know, there's no chance, then why is he bothering even campaigning anymore if it's over?" Santorum said.
The Associated Press contributed to this report.