With back-to-back losses in the Deep South Tuesday night, Newt Gingrich suffered a third defeat: He lost any of the remaining logic behind his candidacy for the Republican presidential nomination. 
 
 His claims to primacy in the South after winning the South Carolina and Georgia primaries evaporated with losses in both Mississippi and Alabama. 
 
 Adding to the sting? The former House speaker who used to represent the Atlanta suburbs in Congress lost both to Rick Santorum, a former senator from the North - Pennsylvania. 
 
 In addition, the fig leaf Gingrich has claimed as the target of relentless and excessive negative advertising from rival Mitt Romney dissolved as Santorum started to win contests and he himself became the target of the former Massachusetts governor’s wrath. 
 
 Santorum has shown an ability to win in spite of it, not lose because of it. 
 
 That leaves the final argument Gingrich has made: that he is the conservative alternative to the “Massachusetts moderate” he has branded Romney. 
 
 A string of wins not just in the South but also the Midwest has lent credence to Santorum’s claim that, rather, he is the true right-wing alternative to Romney. 
 
 It also buttresses his argument that he could fare even better in his quest for the nomination if Gingrich quit the race so he could go head-to-head with frontrunner. 
 
 Even before the polls closed, Gingrich was portending primary disaster, with his staff issuing a memorandum offering a preemptive justification for him remaining a candidate should he lose both of the evening’s contests. 
 
 Senior Adviser Randy Evans and Political Director Martin Baker argued that “Gingrich is well positioned to win the GOP nomination.” 
 
 They noted that heading into Louisiana, only states with a total of 1,141 possible delegates will have voted - short itself of the 1,144 needed for the nomination. 
 
 “The sequencing and pace of the second half favors Newt. When this process started, Newt’s team had two goals: block an early Romney nomination; and plan for a sequenced and paced second half. Newt stopped Romney in South Carolina and subsequently weathered a multi-million dollar barrage of attacks in Florida, surviving to win in Georgia on Super Tuesday,” wrote Evans and Baker. 
 
 “Here is the bottom-line reality: this nomination will not be decided until the fourth quarter – and that is not until June. It also means that the candidate who closes strongest in this race is going to win,” they added. “So buckle up. This race is not going to be won or lost over backroom deals or endless and mind-numbing discussions in the media over delegate counts.” 
 
 The campaign also tried to dispel the ongoing speculation about his candidacy ending by issuing a schedule with seven stops in Illinois between today and Thursday. 
 
 Gingrich himself told his supporters in a non-concession speech: “If you’re the frontrunner and you keep coming in third, you’re not much of a frontrunner.” 
 
 The Gingrich campaign wasn’t the only one with overly optimistic expectations for Tuesday. 
 
 Tim Pawlenty, the former Minnesota governor and onetime GOP candidate who now supports Romney, told CNN: “The resilience of Mitt Romney is starting to show through. When he was way behind in Florida, he came back and beat Newt Gingrich. When he was behind in Ohio, he came back and beat Rick Santorum. The same in Michigan and some other places.” 
 
 He added: “I mean if Mitt Romney does well in those Southern states tonight, the script gets rewritten. I mean that’s a breakthrough moment.” 
 
 The candidate himself was strident. 
 
 “Senator Santorum is at the desperate end of his campaign,” Romney told CNN. “I mean, he’s far behind in the delegate count. He’s far behind in the popular vote count. If you look at the math of how many delegates he’d have to win to become the nominee, it’s a very difficult road for him.” 
 
 In a statement after the results were in, Romney said: “I am pleased that we will be increasing our delegate count in a very substantial way after tonight. Ann and I made a lot of new friends in Alabama and Mississippi and we look forward to campaigning in those states in the general election.” 
 
 Senior adviser Eric Fehrnstrom told CNN that Romney’s goal was not to win an “away game” in the South, but to secure one-third of the delegates up for grabs Tuesday. 
 
 Doing so, he argued, would maintain a status quo in the overall campaign standings. 
 
 “Look, this is a delegate contest,” said Fehrnstrom. “Once the dust clears, you’ll be able to look and see that there really will be no ground that our opponents have made up against Mitt Romney.” 
 
 Santorum scoffed at that assessment through the day and during his victory remarks Tuesday night in Lafayette, La., where he had pre-positioned in anticipation of that state’s primary next week. 
 
 “Well, for someone who thinks this race is inevitable, he spent a whole lot of money against me for being inevitable,” Santorum said in a shot at Romney. 
 
 He added that he would “compete everywhere,” and said: “The time is now for conservatives to pull together.” 
 
 The former senator argues that he is the conservative of choice because he can compete against President Obama on all issues, including health care, where he says Romney will falter because he signed a universal health care law in Massachusetts that was the model for Obama’s federal plan. 
 
 The fourth and final candidate in the race, Representative Ron Paul of Texas, exceeds even Gingrich in being a longshot for the nomination. 
 
 Through Tuesday night, he continues to be the only candidate who has not won either a primary or a caucus. 
 
 He largely skipped the South, despite being a Texan, and instead is concentrating on the Illinois primary next week. 
 
 His campaign touted a rally he is holding today with over 1,000 voters at the University of Illinois in Champaign, Ill. 
 
 As impressive as that number may be, though, if it doesn’t translate into votes, it won’t help him advance toward the goal he, Gingrich, and the others share: being elected president of the United States. 
 
 Glen Johnson can be reached at johnson@globe.com. Follow him on Twitter @globeglen. ||||| Story highlights Gingrich suffers devastating losses in Mississippi and Alabama 
 
 Gingrich has lost ground among key GOP voting blocs 
 
 Santorum has two big wins Tuesday, but has a tough climb toovercome Romney 
 
 Santorum and Gingrich hope to prevent Romney from winning a majority of delegates 
 
 If Newt Gingrich can't win Alabama and Mississippi, where can he win? The former House speaker fell short in the heart of Dixie on Tuesday, and it's not clear where he goes from here. 
 
 Approaching the halfway mark of the primary season, Gingrich has finished first in a grand total of two states: South Carolina and his home state of Georgia. 
 
 Geographically, bright red Alabama and Mississippi were virtual home turf for the former speaker -- two must-win states for him to at least claim the title of regional powerhouse. 
 
 Compared to South Carolina and Georgia, however, there was a clear, critical decline in Gingrich's support among several key groups on Tuesday. 
 
 Among self-described very conservative voters, Gingrich won 33% of the vote in Mississippi and 37% in Alabama. In South Carolina and Georgia, he won 48% and 53%. 
 
 Among evangelical or born-again voters, Gingrich won 30% of the vote in Mississippi and 31% in Alabama. In South Carolina and Georgia, he won 44% and 50%. 
 
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 Among strong tea party supporters, Gingrich won 34% of the vote in Mississippi and 38% in Alabama. In South Carolina and Georgia, he won 48% and 55%. 
 
 Similar declines among all three voting blocs occurred in comparison to the Florida Panhandle -- a traditional Deep South region. Gingrich narrowly won the Panhandle during the Sunshine State's January 31 primary, according to exit polls. 
 
 Last week, Gingrich spokesman R.C. Hammond said the former speaker had to win Alabama and Mississippi in order to remain viable. Gingrich later asserted that he's going on to the national convention in Tampa no matter what happens. 
 
 Bravado aside, at some point the money dries up and voters stop listening. For Gingrich, that point may have come Tuesday night. 
 
 "If (Gingrich) can't win in the South, he needs to go," said Erick Erickson, editor-in-chief of the conservative RedState.org. 
 
 If Gingrich does go, Santorum will get the one-on-one challenge to Mitt Romney he's been all but pleading for. Romney told CNN Tuesday afternoon that Santorum is facing a "desperate end" to his campaign. Santorum's big wins on Tuesday night indicate that end is anything but nigh. 
 
 "It's just the beginning," Santorum spokesman Hogan Gidley said. 
 
 "This is a grassroots campaign for president," Santorum told a group of supporters in Louisiana Tuesday night. It's managing to "defy the odds day in and day out." 
 
 This race has now become an arduous delegate slog. The first man to claw his way to a bare majority of 1,144 wins. Heading into Tuesday, Romney had 459 delegates, Santorum had 203, and Gingrich had 118, according to CNN estimates. Ron Paul trailed badly, with 66 delegates. 
 
 Prior to Tuesday, Romney needed to win roughly 48% of the remaining delegates to go over the top. Santorum needed about 66% of the remaining delegates, and Gingrich needed 72%. 
 
 Given the calendar and the GOP's rules regarding the proportional allocation of delegates, it's tough to see a scenario under which anyone overtakes Romney. Santorum, Romney, and Gingrich each won roughly a third of the combined delegates at stake in Mississippi and Alabama. 
 
 Realistically, the name of the game for Santorum -- and Gingrich if he goes on -- is to prevent Romney from hitting the 1,144-delegate mark and push for a contested convention when the Republicans meet in Tampa in August. 
 
 Can it be done? Most analysts still expect Romney to eventually seal the deal in May or June, but the GOP's conservative base continues, on the whole, to be remarkably resistant to calls to fall in line behind the frontrunner. 
 
 "If we go to a convention, we would be signaling our doom in terms of replacing President Obama," Romney told Fox News earlier this week. "That will not happen." 
 
 There hasn't been a seriously contested convention since Gerald Ford and Ronald Reagan battled down to the bitter end 36 years ago. The odds of another contested convention are long, but the game of presidential politics is anything but predictable. ||||| Photograph by Sean Gardner/Getty Images. 
 
 Mitt Romney said Rick Santorum was at the "desperate end of his campaign," by which he apparently meant the winning end. The Pennsylvania senator won the primaries in Alabama and Mississippi. He is now the leading conservative alternative to Mitt Romney, though Newt Gingrich promised to take his fight all the way to the Republican convention. Mitt Romney, who came in third in both states, is approaching the qualities of some cursed mythological figure who gets stronger on the outside while his insides decay: With each contest, Romney gains delegates but appears to get weaker. 
 
 In Alabama, Santorum won with 35 percent of the vote. Gingrich and Romney both earned 29 percent. In Mississippi, Santorum captured 33 percent of the ballots to Gingrich’s 31 percent and Romney’s 30 percent. The Republican presidential race is holding the pattern that first emerged on Super Tuesday: It remains a race of mathematics versus a movement. Though Romney lost the marquee contests of the evening, he was expected to do well in Hawaii and American Samoa, perhaps giving him the most delegates of any candidate for the evening. The math is still on his side: Romney has won more states, has more delegates, and hundreds of thousands more Republicans have voted for him. But the momentum and energy of the night belonged to Santorum who continues to captivate the grassroots heart of the party. "Ordinary people across this country can defy the odds," said Santorum about the message of the evening and the message of his campaign. "This campaign is about ordinary folks doing extraordinary things, kinda like America." 
 
 Being president requires grit, perseverance, and drive and, by those qualities, Santorum has proven himself for the job. Romney once again vastly outspent him in the contests. Santorum also faced a persistent challenge from Newt Gingrich who was playing on the familiar ideological and cultural turf of the South. 
 
 
 
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 Santorum won by capturing his normal mix of evangelical voters and strong conservatives, but his win wasn't rock solid. In Alabama, 36 percent of voters said defeating Barack Obama was their No. 1 priority, and only 15 percent said Rick Santorum was the best man for that job. Fifty-one percent believed Romney was best equipped to win in the general election. In Mississippi, 39 percent chose defeating Obama as the top quality they sought in a candidate, and Santorum lost by 24 points to Romney on that score, with only 22 percent of the voters picking him. In the same state, 49 percent said they thought Romney could defeat Obama. Half as many said the same of Santorum. In Alabama, when voters were asked who could best handle an international crisis, Santorum received the lowest marks of the three candidates with 21 percent to Romney's 28 percent and Gingrich's 40 percent. 
 
 Santorum's argument for why he will take the convention by storm in Tampa, Fla., relies on his emerging position as the conservative juggernaut. But if the majority of voters have doubts that he can beat Obama or handle an international crisis, it will be hard for him to thunder into the convention as the obvious choice. 
 
 The Romney campaign had hoped for a win in Mississippi and a strong showing in Alabama. This is the downside of lurching forward for the knockout punch; sometimes you land on your face. In reality, though, no one should have expected him to do well in these Southern states. The Republican voters that dominate Alabama and Mississippi are precisely the kind with whom he has the biggest problem winning—evangelicals and those who identify themselves as very conservative. Eighty-four percent of Mississippi voters identify themselves as evangelicals. On Tuesday, there may have been more religious conservatives in voting booths than you’ll ever find in church pews on Sunday. 
 
 Still, Mitt has a problem. As Newt Gingrich put it, "If you're the front-runner and you keep coming in third, you're not much of a front-runner." He has a point. Though both of Romney’s presidential campaigns have stressed the word strong in speeches and television ads, he is increasingly being hounded by the opposite word: weak. Indeed, it may follow him all the way to Tampa. Bill Clinton managed to revive himself in 1992, but he was a natural politician and he had a personal story that more people found appealing. Mitt Romney can’t be both the Republican front-runner and the Comeback Kid. 
 
 The Santorum campaign wants Gingrich out of the race. Though Santorum’s bid remains fragile, he has consistently beaten Gingrich. He would have a better shot at beating Mitt Romney in future states if he was the only alternative, since he would win a larger share of Gingrich's voters (though he certainly wouldn't win all of them). "The time is now for conservatives to pull together," Santorum said in his victory speech, calling a two-man race the best chance to win the election. Gingrich, who is the weakest of the three candidates, boasted that he was the only one who could beat Obama in a debate, an argument he says will help him convince unbound delegates at the convention. It's a big long shot and Gingrich's rationale for staying in the Republican primary rests on soft logic. On Tuesday night, he boasted about his viability because, he said, he won delegates despite losing. It was precisely the same argument Romney made—and that Gingrich claimed revealed Romney as weak. 
 
 The next big test for Romney's long slog to the nomination comes in Illinois. It's a no-excuses state. The southern part of the state, which is rural and conservative, favors Santorum, but not so much that Romney can pretend it's like Alabama or Mississippi. He's got crucial advantages in the Chicago suburbs. Illinois is a state like Michigan or Ohio, where Romney's financial and organizational strength should give him the edge. If Santorum were to pull off a win, it would be a state where he could legitimately say he made inroads into the Romney base, something he has failed to do anywhere so far.
– Newt Gingrich lost both Mississippi and Alabama last night, and the calls for him to drop out have risen to a deafening roar. Here's what pundits are saying: "If Newt Gingrich can't win Alabama and Mississippi, where can he win?" asks CNN. The states are "virtual home turf" for the ex-speaker. Dig deeper, and the numbers keep looking bad; Gingrich saw sharp declines among key groups like very conservative voters and evangelicals. Gingrich "lost any of the remaining logic behind his candidacy for the Republican presidential nomination," writes Glen Johnson of the Boston Globe. He can't even claim he was derailed by Mitt Romney's attack machine—Rick Santorum "has shown an ability to win in spite of it." NPR notes that it's now impossible for Gingrich to get the 1,144 delegates needed to beat Romney. "Gingrich has long been an advocate for thinking 'outside the box,' but lately he has moved outside the box where one finds the calculator, abacus, and the times table." "It is time for Santorum vs. Romney and let the chips fall where they may," agrees Erick Erickson of Red State. A one-on-one contest will give Romney "a run for his money he needs to become a candidate conservatives can potentially rally around." But don't hold your breath. Gingrich's advisers tell the Wall Street Journal that he's staying in—purely to make sure Romney doesn't get enough delegates to clinch the nomination.