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For the Republican campaigns, one critical issue is delegates. If you count the presidential primary wins by state, the race might appear to be wide open. But if you measure by who's won the most pledged convention delegates, Mitt Romney is clearly in the lead. And the Romney campaign insists their man is so far ahead there's no way his rivals can catch up. NPR's David Welna has the latest on the delegate derby.
DAVID WELNA, BYLINE: Over the weekend, according to NPR's tally, Mitt Romney won 17 more pledged delegates, while Rick Santorum racked up 36. Ron Paul got two, and Newt Gingrich got none. Still, at this point overall, Romney has accumulated 357 delegates, while Santorum, his closest rival, has garnered less than half that many. This morning in Mobile, Romney told Fox News it's that delegate lead that matters in this race.
MITT ROMNEY: This is all about delegates, and at this stage, we're putting together as many delegates as we can. We've got a good solid lead. I've got, by far, the most votes among Republicans so far, so we're hoping to be able to get the nomination at some point.
WELNA: Just when that point might be, Romney did not say. But he portrayed his victory as inevitable.
ROMNEY: We're winning this, and I expect that we're going to get the nomination.
WELNA: An hour's drive west in Biloxi, Rick Santorum was disputing Romney's rosy delegate scenario on NBC.
RICK SANTORUM: We're going to move to states where I'm going to have much more of an advantage. We're going to move to states that Governor Romney has proven no ability to really be successful. So the math is not the issue. The issue is vision. The issue is that Governor Romney, having outspent me 10-to-1, is still not able to close the deal and is not on a path himself to get to this.
WELNA: And Santorum made his own prediction as to who'll eventually come out on top in this fight.
SANTORUM: We're going to be the nominee.
WELNA: For Santorum, the race at this point seems to be more about keeping Romney's delegate tally below the magic number of 1,144 than getting to that number himself. John Brabender is a top Santorum campaign adviser.
JOHN BRABENDER: Romney has a great deal of problems. Number one, getting to the number himself. Second of all, we believe that there will be states that will help us dramatically catch up to him. And third of all, if this did go to a convention, the problem with Romney is that he's seen as the moderate. And at conventions, historically, the conservatives do better than the moderates.
JOHN MORGAN: Senator Santorum's campaign may be falling prey to the two-letter word upon which most tragedies build, and that's if.
WELNA: That's GOP demographer John Morgan, who's not associated with any of the campaigns. Santorum, he says, has built his hopes on Republicans arriving in Tampa for their convention without anyone having won the delegate race.
MORGAN: He still has to get a lot of delegates accumulated between now and then, and then prevent Governor Romney from getting to a majority. Meanwhile, he has to continue raising money, and Speaker Gingrich is not likely to get out right away, if at all.
WELNA: And then there's Ron Paul. Jesse Benton, who's Paul's communications director, says the Texas congressman also aims to keep anyone from getting a majority of the delegates before the convention.
JESSE BENTON: If another candidate - Governor Romney, for example - reaches 1,144 hard-bound delegates before Tampa, then we'd likely be ready to concede. But at this point in time right now, we see this as wide open. We think we can block any other candidate from getting to 1,144.
WELNA: Could such a scenario really happen and lead to a brokered convention? Perhaps, says Davidson College delegate count expert Josh Putnam.
JOSH PUTNAM: It's certainly possible that Romney does not get to 1,144. But I think the most likely scenario is that the math just becomes so impossibly difficult for Santorum and Gingrich and Paul that at least Gingrich and Santorum will see the writing on the wall and hang it up.
WELNA: Because, as Putnam argues, no GOP contender knows the rules about delegates better and has lined up more of them than the candidate who turned 65 on Monday: Mitt Romney. David Welna, NPR News, Washington.