Mitt Romney and his wife, Ann, thank supporters Tuesday night in Boston after his Super Tuesday wins.

Following a not-so-clear Super Tuesday showing, who will remain standing? Wednesday night at 9 ET, Piers Morgan talks with Cindy McCain about what it’s like to be in the race for president.

Story highlights

NEW: Newt Gingrich must win Alabama and Mississippi, his spokesman says

NEW: Mitt Romney predicts he will secure the nomination before the GOP convention

A Rick Santorum adviser says Romney seeks to disenfranchise voters by ending the race

Super Tuesday: Romney wins six states, Santorum three, and Gingrich claims Georgia

CNN  — 

Mitt Romney’s campaign tried Wednesday to put the best possible spin on Super Tuesday’s mixed verdict, releasing a memo arguing that it is now nearly impossible for his opponents to catch him in the Republican presidential race.

“Super Tuesday dramatically reduced the likelihood that any of Gov. Romney’s opponents can obtain the Republican nomination,” said Rich Beeson, the campaign’s political director. “As Gov. Romney’s opponents attempt to ignore the basic principles of math, the only person’s odds of winning they are increasing are President Obama’s.”

According to CNN’s latest count, Romney now has 429 delegates, compared with 169 for Rick Santorum, 118 for Newt Gingrich and 67 for Texas Rep. Ron Paul. A candidate needs 1,144 delegates at the Republican convention this summer to secure the nomination to face President Barack Obama in November.

Romney also expressed confidence, telling CNBC on Wednesday that “we’ve got the time and resources and a plan to get all the delegates.”

“We think that will get done before the convention,” Romney said. “One thing I can tell you for sure is there’s not going to be a brokered convention where some new person comes in and becomes the nominee. It’s going to be one of the four people that are still running.”

None of Romney’s opponents “succeeded in closing (the) delegate deficit” Tuesday, and “the calendar ahead offers them dwindling opportunities to close the gap,” Beeson said. He called Super Tuesday a “one-time opportunity” to reshape the race.

Among other things, Beeson said that there are now few major delegate prizes remaining and that most of the states yet to vote have rules requiring a proportional allocation of delegates – a reality that makes it hard to narrow Romney’s lead.

Santorum and Gingrich have argued otherwise, insisting there is still an anti-Romney majority within the Republican Party that can unify in the weeks ahead.

“What Romney is trying to do is call the game before it’s even halftime because he has a lead,” Santorum adviser John Brabender said, adding that Romney wants to “disenfranchise Republican primary voters.”

Former candidate Herman Cain, who has campaigned with Gingrich in recent weeks, also called talk of anyone pulling out premature.

“Folks, only 1/3 of the delegates have been allotted! It’s too soon to call on a candidate to withdraw from the race!” Cain posted on Twitter.

The Romney campaign shared more good news Wednesday when it announced it raised $11.5 million in February – the second-best month of fundraising to date. That compared with the roughly $9 million in the same month raised by Santorum’s campaign.

In a fundraising e-mail to supporters Wednesday, Santorum portrayed himself as the underdog who better fits what the nation wants.

“Americans want a scrappy, determined, unflappable fighter that understands where they came from and what they are struggling with,” the e-mail said. “There’s only one candidate in this race that meets those criteria (hint: It’s not Mitt Romney).”

Next on the calendar: Kansas holds its caucuses Saturday, followed by contests in Alabama, Mississippi and Hawaii on Tuesday.

Several U.S. territories will also have the chance to weigh in over the next week, including Guam, the Virgin Islands and American Samoa.

Romney substantially increased his delegate lead on Super Tuesday but failed by most accounts to deliver a knockout blow. He squeezed out a razor-thin popular vote win in the bellwether state of Ohio while carrying his home state of Massachusetts, plus Idaho, Vermont, Virginia and Alaska.

Santorum won North Dakota, Oklahoma and Tennessee, while Gingrich cruised to victory in his home state of Georgia.

Paul failed to win in any of the states up for grabs.

iReport: Why can’t Romney seal the deal?

Romney was aided by his opponents’ organizational failures. Santorum failed to meet the eligibility requirements for a number of delegates up for grabs in Ohio, and neither Santorum nor Gingrich qualified for the Virginia ballot.

Despite his opponents’ problems, however, Romney still demonstrated significant weakness with elements of the Republican base. Evangelical voters, Southerners, strong tea party backers and rural residents continued to largely reject the former Massachusetts governor’s candidacy.

A substantial number of voters also indicated concern that Romney – a wealthy former venture capitalist – cannot adequately relate to their daily struggles. In exit polls, 34% of Ohio voters said Santorum best understands the problems of average Americans, compared with only 22% for Romney.

Romney – generally perceived as more moderate than Santorum or Gingrich – “still has a problem with the base,” said Ari Fleischer, a CNN contributor who was press secretary for President George W. Bush. “That base problem may make him attractive to independents if he gets to a general” election but can work against the former governor in the primary season.

For Gingrich, who represented Georgia’s 6th Congressional District for two decades, the home state victory provided a new boost after a string of defeats.

However, his poor showing elsewhere on Super Tuesday caused his campaign to change strategy, canceling a visit to Kansas in order to focus on what a spokesman called must-win primaries in Alabama and Mississippi.

A reporter asked Gingrich spokesman R.C. Hammond on Wednesday if Gingrich must win both Southern states to remain “credible,” a euphemism for staying in the race, and Hammond replied: “Yes.”

“A big win in Georgia kept us in the race,” he said. “Big wins in Alabama and Mississippi will add even more fuel to the tank.”

Winning our Future, the super PAC supporting Gingrich’s candidacy, will continue to run ads in Kansas, senior adviser Rick Tyler said.

Santorum’s victory in Tennessee hurt Gingrich’s strategy in the South after the former House speaker’s triumphs in South Carolina and now Georgia. Santorum’s camp now plans to buy about $1 million in ads in Kansas, Alabama and Mississippi, a source with the campaign said.

Romney sounded like the presumptive GOP nominee, focusing his attention on the president at a victory rally in Boston on Tuesday night.

Citing national unemployment that remains above 8%, he said the figure is just an “inconvenient statistic” in the eyes of the Obama administration.

“But those numbers are more than data on a spreadsheet; they are worried families and anxious faces,” said Romney, who was interrupted repeatedly by chants and cheers. “And tonight, I’d like to say to each of them: You have not been forgotten. We will not leave you behind. Our campaign is on the move, and real change is finally on the way.”

Romney also signaled a continued battle for his campaign.

“Tonight, we’ve taken one more step towards restoring the promise of America,” he said. “Tomorrow, we wake up and we start again. And the next day, we’ll do the same. And so it will go, day by day, step by step, door by door, heart to heart.”

Santorum also focused on Obama in his remarks to supporters Tuesday night, saying the president’s policies threatened the individual liberty of Americans. But he targeted Romney as well for his health care law in Massachusetts, arguing it was the model for Obama’s federal health care reforms detested by conservatives.

“I’ve never been for a mandate at a state or a federal level,” Santorum said in challenging the requirement in both the Massachusetts and federal laws for people to have health coverage.

Despite lingering concerns about Romney’s conservative credentials on health care and other issues, the former governor’s campaign was bolstered by endorsements from several leading conservatives this week, including House Majority Leader Eric Cantor, R-Virginia; Oklahoma Sen. Tom Coburn; and former Attorney General John Ashcroft.

On Wednesday, Romney’s campaign announced the endorsement of former Alabama Gov. Bob Riley, hoping to get a boost ahead of next week’s primary.

CNN’s Jim Acosta, Dana Bash, Gregory Wallace, Shawna Shepherd, Gloria Borger, Chelsea J. Carter and Paul Steinhauser contributed to this report.