BILOXI, Miss. — Rick Santorum's strategy for becoming the Republican presidential nominee comes down to this: prevent Mitt Romney from winning enough delegates to arrive at the GOP convention this summer with a mandate and persuade delegates to ignore election results in their states.
The hope is that delegates will go with Santorum as the more conservative option over front-runner Romney. But there's a hitch: Newt Gingrich is refusing to quit the race.
It's a long-shot gamble for a candidate who began as long shot and badly trails Romney in delegates leading to the August convention in Tampa, Fla., where Republicans will pick a challenger to President Barack Obama.
Adding to Santorum's money and organizational challenges is the fact that Gingrich is splitting the conservative vote and is dismissing pressure by Santorum to drop out after losing this past week in Alabama and Mississippi.
Not that Santorum, who has defied expectations to become Romney's chief challenger, seems daunted by the odds.
"You've been listening to math class and delegate math class instead of looking at the reality of the situation," the former Pennsylvania senator told reporters in Biloxi last week. "It's going to be very difficult for anyone to get to the number of delegates that is necessary to win with the majority at the convention."
"This isn't about math," Santorum says. "This is about vision."
So far, it's all adding up for Romney.
He has captured 495 delegates, more than all of his rivals combined. Santorum stands at 252, Gingrich has 131 and Ron Paul is at 48, according to an Associated Press projection. That puts Romney on pace to win the required 1,144 delegates in June.
Romney's advisers claim it would take an "act of God," as one put it, for Santorum to take the lead in the delegate count. "If he is able to pull off a miracle so be it. He'll be the nominee," Romney said.
Santorum, whose Catholic faith is central to his campaign, was not amused. "I don't know about him, but I believe in acts of God," Santorum said.
One of his strategist's, John Patrick Yob, put it another way in a recent memo that said the Romney team's focus on the delegate count was an effort to distract from what Santorum's campaign claims is trouble the front-runner faces in county, district and state conventions, where delegates are locked in.
Historically, delegates take their cues from the voters who participate in the primaries and caucuses.
Santorum sees himself as the preferred candidate of conservatives, given victories in the Deep South and elsewhere. He's betting that he can buck tradition by getting delegates at the local level to thwart the will of the people and side with him over Romney.
Santorum hopes to ride into Tampa with enough support to deny Romney the nomination on the first ballot. Under this scenario, delegates would be free, in many cases, to back whomever they wanted.
Yob's memo said Romney "will perform worse on subsequent ballots as grassroots conservative delegates decide to back the more conservative candidate. Subsequently, Santorum only needs to be relatively close on the initial ballot in order to win on a later ballot as Romney's support erodes."
But there are hurdles Santorum is overlooking.
It takes money and organization to twist arms at local, county and state conventions; Santorum lags in both. Also, Gingrich is still kicking and has a chunk of conservative support.
With Mississippi and Alabama showing that Santorum had defeated Gingrich on what essentially was the former Georgia lawmaker's home turf, Santorum said it was time for conservatives to unite against defeat Romney. Translation: Gingrich should step aside.
About half the states still await the chance to vote. Santorum wants to make the remaining contests a head-to-head match against the former Massachusetts governor, winning beyond conservative areas in hopes of denying Romney the clinching number.
Santorum is competing Tuesday in Illinois, friendly Romney territory, but also looking ahead to Louisiana's primary next Saturday. Santorum is trying to make the case that there isn't much daylight between Romney and Obama, and that the Democratic incumbent has the edge in that general election matchup.
Romney is "a Massachusetts moderate who put in Romneycare, who ran as a pro-choice candidate and a strong supporter of gay rights, someone who has increased taxes, expanded the size of government," Santorum said recently, citing issues where he says Romney and Obama are the same.
As governor, Romney helped develop a statewide health care plan that Obama and others have said is the basis for the national plan Obama championed.
Santorum hopes to benefit from the deep skepticism among social conservatives about Romney, a Mormon who has struggled with this group of voters since his failed 2008 bid.
According to exit polls conducted in Alabama and Mississippi, only about 1 in 5 very conservative voters backed Romney, while 7 in 10 said his positions on the issues were not conservative enough.
Romney has won among "very conservative" voters in just four states where exit or entrance polls were conducted: Two where he's lived (Massachusetts and New Hampshire) and two with a significant Mormon population (Nevada and Arizona).
Still, it takes money and manpower to seize the moment. Santorum is raising money, but far less than Romney, and he has virtually no organization.
In the end, Santorum is counting on the GOP base's apparent demand for ideological purity in the nominee to trump time-tested techniques for winning the nomination.