Washington (CNN) -- Coming off another victory in conservative territory, Rick Santorum on Sunday rejected arguments that frontrunner Mitt Romney's lead in the delegate count for the Republican presidential nomination was virtually insurmountable.
"This isn't a mathematical formula -- this race has a tremendous amount of dynamics," Santorum told the NBC program "Meet the Press" the day after winning the Kansas caucuses to bolster his second-place standing behind Romney.
According to CNN's estimate, Romney had 458 delegates, compared with 203 for Santorum, 118 for former House Speaker Newt Gingrich and 66 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's campaign said the candidate won caucuses in the Virgin Islands, Guam and the Northern Mariana Islands on Saturday to bolster his delegate lead despite losing Kansas to Santorum.
However, the Kansas loss showed Romney's continued inability to win a conservative state, and results generally show that combining the support of conservatives Gingrich and Santorum exceeds the backing for Romney.
The focus of the campaign shifts to the conservative Deep South for Tuesday's primaries in Alabama and Mississippi, while Hawaii and American Samoa will hold caucuses on the same day.
On Monday, comedian Jeff Foxworthy -- who is popular among Southern conservatives for his redneck jokes and Blue Collar Comedy Tour -- will campaign for Romney in Mississippi and Alabama.
Santorum and Gingrich are vying to oust the other to become the sole conservative challenger to the more moderate Romney as the campaign heads into a series of contests in coming weeks including major states such as Illinois, Louisiana, Maryland and Wisconsin.
Gingrich insisted Sunday he was in the campaign for the long haul, despite calls from Santorum backers for him to drop out so that conservative voters can coalesce around one candidate.
So far, Gingrich has won two Southern states -- South Carolina and Georgia -- in a strategy focused on building a Deep South stronghold.
Santorum's Super Tuesday victory in Tennessee dented Gingrich's plan, and a Gingrich spokesman said last week the candidate had to win both Alabama and Mississippi on Tuesday to remain credible. Gingrich, however, sounded intent on dispelling that notion Sunday.
"I think we'll win both," he told "Fox News Sunday," adding that he started from behind but "I think we're probably polling ahead in both states right now."
Later on the CBS program "Face the Nation," Gingrich sounded less certain of a double victory but equally determined to remain in the race well beyond Tuesday.
"We're going to get a lot of delegates in both Mississippi and Alabama, and I think the odds are pretty good that we'll win them," Gingrich said, later adding that he was "committed to going all the way to Tampa" for the Republican convention in Florida in August.
An American Research Group survey last week of likely Republican primary voters in Mississippi showed Gingrich with 35% support to 31% for Romney, 20% for Santorum and 7% for Paul. The poll's four percentage-point sampling error meant Gingrich and Romney were in a statistical tie.
Gingrich is focusing his campaign on energy policy, complaining that Obama is bowing to foreign oil suppliers such as Saudi Arabia and the environmental lobby by not fully exploiting U.S. oil reserves.
He also took aim at Santorum on Sunday, saying on CBS that the former Pennsylvania senator was part of big spending in Congress while Gingrich's record involved balancing the budget.
"I represent the Reagan tradition of very large ideas," Gingrich said. "He represents being a team player on a Washington team."
Santorum campaigned in Mississippi after his talk show interview Sunday, telling an event in Tupelo that he can win enough delegates to secure the nomination ahead of the convention, or at least prevent Romney from reaching the winning threshold.
"We feel good we're in a position to win it," Santorum said, adding "if we have to go to an open convention, we like our chances just as well."
He took exception with the media reporting Romney as holding a wide lead in delegates won so far, saying "the news agency apportion delegates that have nothing to do with the reality of where the delegates are going to be."
For example, Santorum said he expected to win a strong majority of Iowa's delegates despite a narrow victory in the state's caucuses back in January.
"These numbers are going to change dramatically and as you also know, a lot of these delegates are uncommitted," Santorum said.
Santorum's victory in Kansas -- which his top rivals essentially ceded -- came on the heels of his three victories on Super Tuesday last week. His campaign said tea party loyalists and conservatives continue to rally around him, and he went after Romney on Sunday as a shifting candidate with no loyalty to conservative principles.
"He went out and misled voters that somehow or another he was not for mandates at the federal level when in fact he was," Santorum told NBC of Romney's position on health care reform. " ... He's repeatedly had big government solutions and then gone out and told the public bald-faced that he didn't do the things that he did."
On climate change, Santorum said, Romney previously backed capping carbon emissions as part of a policy rejected by most conservatives that blames industrial pollution for contributing to global warming.
" And now that it's not popular, now that the climate changed, guess who changed along with it? Governor Romney," Santorum said.
CNN's Gabriella Schwarz and Shannon Travis contributed to this report.