For the last several days, the Romney campaign has been arguing that the delegate math is on their side.

But in a new memo, the Santorum campaign is now countering with this message: Time is on theirs.

The memo from John Yob, who was recently hired to head up the Santorum campaign's delegate-counting strategy, argues that the longer the former Pennsylvania senator stays in the race, the more he stands to benefit.

The primary calendar has been frontloaded to favor Mitt Romney, Yob argues, but a series of contests in May will put the candidate on a path to be competitive for the GOP nomination heading into the August convention.

Also on Santorum's side is the possibility of Newt Gingrich abandoning his bid for the White House. That, Yob contends, would cause many of the former House speaker's delegates to fall Santorum's way. Plus, excited party conservatives could help Santorum pick up more delegates from states that held non-binding primaries and caucuses.

"Despite the Romney campaign's smokescreen, they cannot change the fact that he can't inspire the base of the party, has a delegate problem, and has a very difficult time getting to the majority," Yob says in the memo.

Yob, who held a similar post in John McCain's 2008 campaign, said at this point four years ago there was a very real concern in the Arizona senator's camp about "the possibility of a more conservative candidate staying in the race and fighting us at state conventions across the country." Yob notes that, like McCain, Romney does not have the support of the most active and conservative party members who play a key role in determining national convention delegates.

"Anyone who knows anything about state conventions knows that the most conservative candidate has a big advantage over a moderate candidate. In many cases, this advantage is overwhelming," Yob adds. The memo goes on to cite gains by Santorum and Paul during this weekend's county conventions in Iowa as proof.

The Romney campaign has argued that the math simply does not play out favorably for Santorum, and NBC News has calculated that Santorum will need to win more than 60% of the remaining delegates to secure the nomination.

Also included in the memo is a state-by-state outline of how the Santorum campaign thinks the race will shape up. Tuesday, Yob predicts, will do little to change the dynamic of the race. It infers that Gingrich will drop out after the March 24 Louisiana primary, if not before. Those former Gingrich delegates will likely favor Santorum, Yob feels.

The May 8 contests held in North Carolina, Indiana ,and West Virginia will kick off a month of strong momentum for the campaign that will all culminate in a huge delegate win in Texas on May 29, the campaign believes.

"The situation is only going to get worse for [Romney] and better for Rick Santorum as time passes," Yob writes. "Simply put, time is on our side."

GULFPORT, Miss. – The Republican party will be in trouble come November if Mitt Romney attempts to inspire voters using math, Rick Santorum argued to a roomful of Mississippi supporters on Sunday.

"You have Gov. Romney now saying, 'Oh this race is over that mathematically it can't work," Santorum said.  "When we have our nominee going out there and trying to sell the American public to vote for him because of mathematics, we are in very, very tough shape. This isn't about math. This is about vision, it's about leadership."

Santorum, a former Pennsylvania senator, will need to win 61 percent of the remaining delegates to win the nomination, according to calculations by the NBC News political unit. That’s a tall order, especially with former House Speaker Newt Gingrich remaining in the race and cutting into Santorum's support.

But the Santorum campaign has dismissed the delegate argument, and instead focuses on the upcoming states and the possibility of non-binding delegates coming their way.

As Santorum took his campaign to the South, he continued to stress how his grassroots campaign has been the key to his success, contrasting his style with that of his rivals. He said it is the aggressive schedule of town halls held in Iowa while he was at the bottom of the polls that led to his rise. "You keep going, because every meeting I've had like this, people walk out and they take a sign, they take the card and they say 'I'll make some phone calls,'" Santorum said.

He added, "We haven't run a campaign carpet-bombing people with calls and ads."

Santorum targeted Romney and President Barack Obama over one of the most heavily-used talking points used during this Republican primary – the teleprompter.  "I always believed that when you run for president of the United States, it should be illegal to read off a teleprompter. Because all you're doing is reading someone else's words to people. You know, when you're running for president, people should know not what someone's writing for you after they've had pollsters and speech writers test it."

Santorum also acknowledged some of his own mistakes that have came from not using a teleprompter. "You know we get fired up sometimes and say some things that I wish I had a mulligan on if you will, but if you’re not scripted that’s going to happen," he said.

CAPE GIRARDEAU, Mo. --  Rick Santorum cautioned Missouri voters on Saturday that jobs may not be the most important issue in the November election and laughed off claims by Mitt Romney's campaign that he was not the day's big winner after a decisive victory in the Kansas caucuses.

After new jobs numbers released on Friday revealed more positive signs for the economy, the former Pennsylvania senator warned about the threat of a nuclear Iran and said national security could become the issue of top concern for voters heading into the general election this fall.

"People say, 'Well what’s gonna be the most important, oh jobs, jobs, jobs.' Well maybe not," Santorum told a crowd of 700 Republicans gathered for a Lincoln Day dinner. "We’ve got a country in the Middle East that’s about, potentially about to explode a nuclear weapon, which would change the face of our Earth."

The important role the economy will play in this election has been a central tenet of Romney's campaign. The former Massachusetts governor often cites his experience in the private sector as proof he is best suited to fix the economy. It's an experience he argues no other Republican presidential candidate has. But Santorum's argument Saturday night was that he is the only candidate with the experience to keep America safe.

"We have candidates running around saying they want to run for CEO of America. I’m running to be the commander in chief for America,” Santorum said.

His two stops here came at the end of what was a good day for the presidential hopeful’s up and down candidacy.

Saturday morning, aides said, they raised $85,000 in cash during a fundraiser in Houston, Texas, with the 200 conservatives in attendance pledging another $1.78 million to go toward both the campaign and the pro-Santorum Super PAC "Red, White and Blue Fund." In the afternoon, results came in from the Kansas caucuses that showed him earning a resounding victory.

Also Saturday, Rep. Jo Ann Emerson, R-Mo., announced her support for Santorum. It is one of the few endorsements he has earned from members of Congress he served with during his 16 years on Capitol Hill.

But seeking to counter the positive headlines, Romney's campaign again pointed to the math that they claim falls in their favor.

"Today, Mitt Romney won more delegates than any of the other candidates and continued his momentum and path to getting the delegates needed to secure the Republican nomination," Romney spokesperson Andrea Saul wrote in an email to reporters. Romney racked up wins in Guam, Northern Mariana Islands, Virgin Islands, and Wyoming, a state whose delegate apportionment has yet to be fully settled.

Greeting voters at a later event in a hangar in the Cape Girardeau airport, Santorum laughed off the Romney campaign's assertion. "It's sounding very desperate for a man who supposedly has it in the bag," he said.

"We need a strong contrasting vision for this country and Gov. Romney doesn't provide that and I think the people of Kansas spoke very, very loudly about their concerns about his viability," Santorum added.

The presidential hopeful expressed his profound gratitude to the "Show Me State," which, along with Minnesota and Colorado, gave him three big victories last month that gave new life to his candidacy.  Though Missouri's primary in February awarded no delegates, it proved to be a big win for a candidate who seemed to have stalled out after winning the Iowa caucuses.

“I should be applauding you and not the other way around," Santorum said. "I can say this without hesitation: If it wasn’t for the people of Missouri I wouldn’t be standing here today ... I greatly appreciate the warm reception, and I have to just say again, I do mean that what happened during the primary here and the caucuses in Minnesota and Colorado, gave the country an opportunity to take a second look."

TOPEKA, Kansas -- As he aims to frame the GOP nominating contest as a "two-man race," an aggressive Rick Santorum on Friday attacked rival Mitt Romney as untrustworthy and politically moderate at his core.

"Ladies and gentlemen, we already have one president who doesn’t tell the truth to the American people," he told a crowd of about 250 supporters at a railroad station-turned-museum in Topeka.  "We don’t need another nominated by our party to do the same."

Santorum, seeking a strong showing in upcoming Southern primary contests, accused Romney of planning a swift move away from conservative principles if he wins the nomination.

"The Romney campaign can’t wait to get out of this primary," he said. "Guess why? They can start tacking to the middle now, start getting back in the comfort zone."

In his critique, Santorum zeroed in on Romney's backing of mandated health care coverage during his tenure as Massachusetts governor. Romney says he never advocated for such a requirement on a national level, while Santorum pointed to several recently uncovered video clips as evidence to the contrary.

"Washington insider Rick Santorum is lashing out at Mitt Romney because he can’t accept the fact that it’s nearly impossible for him to win the number of delegates needed to secure the Republican nomination," Romney spokeswoman Andrea Saul responded, pointing out Santorum's statement in a recent debate that he "took one for the team" in helping pass bipartisan legislation. "This is yet another case of Sen. Santorum abandoning principle for his own political advantage."

Kansas Gov. Sam Brownback made an appearance at the Topeka rally, standing in the back of the audience clad in a sweater vest - a garment frequently worn by the presidential hopeful. Brownback told reporters that his presence was no endorsement but was merely intended to show support for the GOP candidates appearing in the state; he also made a stop at an event held by Ron Paul earlier in the day.

Despite a strong performance expected in this weekend's caucuses in Kansas, Santorum's path to victory over Romney remains hazy. 

But Santorum was cheery about that possibility on Friday.

"You know the other day Governor Romney was going through the math of all the delegates and said it would take an act of God for Rick Santorum to get all of the delegates he would need," he said. "Well, I don’t know about him, but I believe in acts of God."

MOBILE, AL -- Standing in front of a retired fighter jet, Rick Santorum on Friday called for voters to make a change in commander in chief and argued that President Obama has not stood up for American troops or for its ally Israel.

Inside the USS Alabama Pavilion, Santorum accused President Obama of abandoning Israel by joining with five other countries offering to resume negotiations with Iran over its nuclear program.

"Yet in the face of President Netanyahu (sic) coming here asking him, imploring the American people to stand by her at her side, the very next day after...the president announced they would start talks with the Iranian government," said Santorum.  "'We got your back,’ [President Obama] said the day when he spoke to AIPAC. And then two weeks later turns his back on Israel again and says well we will negotiate without precondition. This is weakness in the face of hostility."

Santorum has made his hardline stance against Iran a key part of his pitch to Republican voters. He was the only Republican presidential candidate to address AIPAC in person, and he has called for ultimatums for Iran to open up the facilities where nuclear weapons may be developed.

Along with failing to stand up to the potential of a nuclear Iran, the former Pennsylvania senator also accused the president of not standing up for the troops, making reference to a recent incident where a U.S. troop inadvertently burned copied of the Quran.

"American military does something that may offend the sensibilities of people whose sensibilities are easily offended and yet doesn’t stand up for our men and women in uniform as they are fragged, as they are attacked by mobs in Afghanistan," Santorum said. "Ladies and gentlemen, we need a new commander in chief in America."

Santorum spoke to fewer than 100 supporters in an event that organizers say was put together in less than 24 hours.  The GOP candidate did not so much as mention his Republican rivals during the rally.  

Throughout Mississippi and Alabama over the past two days, Santorum has called on voters to deliver the blow that will knock Newt Gingrich out of the race.  A Gingrich spokesman called the southern states must wins for the former Speaker to remain a viable candidate.

Santorum aides have asserted that Gingrich's persistence in the race has split conservative voters and cost Santorum wins in Michigan and Ohio.

Campaigning in an area still feeling the effects of the 2010 BP oil spill, Santorum remained steadfast in his support of offshore drilling. "It is a better option than receiving oil from places in the world that are going to turn around and then use it to attack us," he told reporters after the event.

But at this stop, Santorum abandoned any talk of the social issues that have come to define his candidacy.  Asked why, in the deep South, where social issues are especially important to voters, he shied away from the issues, Santorum said: "Those who follow me a lot know I talk about national security and energy all the time, and it’s an area really of strength for me and not something most people know so we are going to talk about it more."

STEUBENVILLE, OH -- Rick Santorum's campaign is calling on conservatives to pressure Newt Gingrich to abandon his bid for the White House, a senior adviser told reporters tonight.

Senior campaign strategist John Brabender said the key for the campaign going forward will be creating an opportunity to challenge Mitt Romney one-on-one, though Brabender maintained the Santorum campaign would not directly call on Gingrich to drop out of the race.

Slideshow: Voters head to polls on Super Tuesday

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See pictures from around America as 11 states hold contests that will award a combined 424 delegates in the Republican primary.

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"We're never going to call on anybody to get out, but what we are calling is on Tea Party supporters and conservatives is to rally behind the only candidate that has demonstrated over and over again that he's the one who can compete against Mitt Romney," Brabender said.

"The real key right now is, can we get an opportunity to get a one-on-one shot with Mitt Romney," he said. "What we found is, Gingrich did a nice job in his home state, but I don't even think he had a second place anywhere else ... It's time for conservatives to say 'Look, we're going to rally behind one candidate, Rick Santorum."

Speaking to reporters in the high school gym where Santorum spoke just moments earlier, Brabender declared that no matter what the final result in Ohio, it already has been a bad night for Mitt Romney's campaign.

"All I know is after spending nearly $10 million here in Ohio, right now its neck and neck and it's going to be close to a tie, and somebody will win, but not by much.  I don't know how they declare that anything but a disappointment," he said.

Cuyahoga Falls, OH – Making his final pitch to Ohio voters Monday, Rick Santorum called on supporters to vote for a candidate of honor – all the while calling Mitt Romney dishonest for defending the health care legislation he signed as governor of Massachusetts.

"We now find multiple videos and op-eds where (Romney) advocated for... a government-mandated health insurance benefit, something he's been denying throughout the course of this campaign," Santorum told a packed crowd in Westerville, OH. "It's one thing to be for it, it’s another to not tell the truth to the people of this country."

The remarks came shortly after Santorum held a conference call with reporters in which he argued Mitt Romney’s record would undermine his ability to challenge President Barack Obama about health care during the general election.

Romney says the Massachusetts health care law was right for Massachusetts but that he would not have advocated for it as a model for the country. Still, the Santorum campaign continues to point reporters to clips of Romney television appearances as proof that the former governor believed the legislation could work beyond the state borders.

"Now we know that Gov. Romney, for the course of this campaign has told the people of this country something that wasn't true,” Santorum said. “Now it's one thing … to have bad policy. It's another thing to mislead the American public."

Demonstrating its organizational strength, the Romney campaign responded to the Santorum conference call even before it started.

Spokeswoman Andrea Saul blasted out a response: "Over the last several years, Governor Romney has said many times, in many different formats, that his health care reform plan was the right model for Massachusetts, and that it should not be used as a one-size-fits-all national health insurance plan. Governor Romney is a federalist and has always said that states should be free to come up with their own health care reforms.”

Recent polls show the two neck-and-neck in the Buckeye State heading into Super Tuesday.

CHILLICOTHE, OH -- Speaking to several hundred people inside a high school gym Friday, Rick Santorum declared he is running an “insurgent” campaign against a Washington establishment he described as “old boy.”

“We’re running a grassroots, insurgent campaign,” Santorum said, before adding that his own supporters “don’t want what Washington and the old boy network is going to give us again.”

The remarks, an apparent swipe at Mitt Romney, were the latest development in a back-and-forth between the two candidates days before the Super Tuesday contest in Ohio and other key states.

Santorum went to great lengths to paint a picture of his once-long shot candidacy as a populist but viable alternative to Romney’s, telling the crowd his campaign raised about $9 million during February.

“Two thirds of that money came from small-dollar donors,” Santorum said, adding, “two thirds of Governor Romney’s money comes from people who max out at 25-hundred dollars.”

(Per federal elections law, the limit on individual contributions to a national political campaign is $2,500.)

But nowhere was the tension between the two men more evident than in Santorum’s attack on the Michigan Republican Party for awarding a delegate Thursday to Romney, tilting what the Santorum team had assumed was a tied delegate count in Tuesday’s primary in Michigan to a 16-14 haul in Romney’s favor.

“They were so embarrassed yesterday they decided to change the rules after the fact,” said Santorum of the state's Republican Party, which he said “felt bad” that Romney hadn’t won the delegate count outright.

“You know, my feeling on that is conservatives – Americans – play by the rules,” Santorum added.  “We don’t change the rules afterward.”

In a measure of the tightening race here in Ohio, a Romney aide circulated among reporters at the event Friday, offering responses to Santorum’s attacks. 

“He’s sour that he’s just lost three straight states,” said Ryan Williams, a Romney campaign spokesman, of Santorum and the result of contests in Arizona, Michigan and Wyoming this week.  (The Wyoming caucuses straw poll was non-binding.)

Williams added that a rule awarding two “at-large” Republican delegates to the winner of the popular vote in Michigan had been decided by the state GOP prior to the Feb. 28th primary.

The sniping didn’t end there.

In remarks to reporters following his speech, Santorum also commented on a video first reported by ABC News, showing Romney vowing in 2002 to pursue federal money for in-state projects in Massachusetts.

“Hypocrisy, plain and simple,” Santorum said of the video, which was shot during the Massachusetts governor’s race. Romney has made attacking Santorum for the practice of “earmarking” central in his effort to ward off the former Pennsylvania senator.

But among voters Friday, the candidates' attacks on each other didn’t seem to register.

Patty Null, a retired teacher living on social security, said her main concern is Ohio’s flagging economy.

“Our taxes are too high, our utilities are too high,” she said. “We just can’t make it anymore.”

WILLOUGHBY, OH -- Rick Santorum says President Barack Obama has failed to support the U.S. troops and has weakened the military.

"This president has got to stop apologizing for America," Santorum said during an address to 600 Ohio Republicans at a Lincoln Day Dinner here Friday night.  "His gut reaction is always to blame us, to blame our men and women in uniform.  Stop it, Mr. President.  Stand up for our troops.  Stand up for this country."

The former Pennsylvania senator argued that Obama has slashed defense spending while creating new entitlement programs like the health care legislation passed in 2010. He said the president is striving to create an America dependent on the government.

Many have attributed Santorum's second-place finish in the Michigan primary to his fiery rhetoric on the campaign trail. He called the president "a snob" for calling on all Americans to seek higher education, and questioned the president's religious beliefs.

On CNN on Friday, Santorum seemed to acknowledge that the snob comment was over the line, saying "It was a strong term, probably not the smartest thing."

But Friday night, he again went into territory that had drawn criticism from the left and head scratching from some on the right.

"I've gotten some grief in the media lately because, well, I'm a little bit too passionate; I say things that sometimes offend people -- that I talk about government dictating to us and suggested that might not be, you know, a little snobbish for people to do that," Santorum said. "Or I talk about how we have to have traditional values in this country and respect for the dignity of human life and the respect for freedom of religion in this country."

Santorum will spend plenty of time in the Buckeye State leading up to Super Tuesday. Holding the most delegates of all the states voting on March 6, it is largely seen as the state that Santorum needs to win in order to still be considered a top contender for the GOP nomination

"When Ohio whispers, people listen.  When Ohio shouts 'We want a conservative,' this country will stand up and join you," he said.