(CNN) -- Despite calling contests in the South "a bit of an away game" last week, Mitt Romney enters Tuesday as very much a contender to capture either or both the Alabama and Mississippi primaries.
Voters in those states cast their ballots Tuesday, deciding which of the four remaining Republican candidates they feel should challenge President Barack Obama this fall.
There's no clear-cut favorite in either state, according to a pair of polls released Monday.
A poll of likely voters in Mississippi's GOP primary showed Romney slightly ahead of rival Newt Gingrich, 34% to 32%, which was within the margin of error.
Meanwhile, a poll of likely voters in Alabama's primary showed Gingrich, who is from neighboring Georgia, at 34% to 31% for Romney, a gap also within the sampling error.
Rick Santorum trailed in both polls -- 10 points behind Gingrich in Alabama and 12 points behind Romney in Mississippi. The fourth GOP candidate, Texas Rep. Ron Paul, has not campaigned in either state.
Gingrich and Santorum are competing to become the lone conservative survivor in the race against the more moderate Romney for the Republican nomination.
According to CNN's estimate, Romney has 458 delegates, compared with 203 for Santorum, 118 for Gingrich and 66 for Paul. A candidate needs 1,144 delegates at the Republican convention to earn the chance to face Obama in November.
A memo from Santorum's campaign, written by Michigan consultant John Yob, countered the Romney camp's claim that he's the inevitable nominee. "Romney's math doesn't add up," according to the memo, which says the former governor must win more than 50% of remaining delegates in order to capture the nomination.
Romney himself countered, in a Fox News interview Monday, that Santorum would need a "miracle" to cinch enough delegates ahead of the convention.
Even while garnering the most delegates so far, Romney has been unable to attract broad support among the GOP's conservative base.
The former Massachusetts governor is hoping to break through with a win in traditionally conservative territory that has been targeted by Gingrich and Santorum.
In addition to the Alabama and Mississippi primaries, Hawaii and American Samoa hold caucuses Tuesday.
In a bid to assert some Southern appeal, Romney appeared Monday with comic Jeff Foxworthy, who is popular for his redneck jokes and Blue Collar Comedy Tour, in the driving rain in Mobile, Alabama.
Romney spoke about the tight race in the state, saying, "I do need your help. I really do need you guys to get out and get your friends to vote. This could be an election that comes down to a very small margin between the three people running here most aggressively."
Gingrich's campaign has staked his strategy of establishing a Deep South stronghold by winning both Alabama and Mississippi. His two victories so far were in South Carolina in January and last week in Georgia, which the former House speaker represented in Congress for two decades.
However, Santorum's Super Tuesday victory in Tennessee dented Gingrich's plan. On Sunday, Gingrich said he is in the campaign for the long haul despite calls from Santorum backers for him to drop out so conservative voters who have reservations about Romney can coalesce around one candidate.
"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 on the CBS program "Face the Nation," later adding that he is "committed to going all the way to Tampa" for the Republican National Convention in August.
Santorum, a former Pennsylvania senator, continued to portray himself as the most viable conservative alternative to Romney, telling Atlanta radio talk-show host Neal Boortz on Monday that Gingrich hasn't run strongly outside the South.
"He has never finished above third, he has mostly finished fourth, he is even finishing mostly behind Ron Paul now," Santorum said. "Here in Kansas again he finished out of the money.
"We're winning in the South, we're winning in the West, in the Midwest, we're winning really all across the country. And I understand Newt's sort of drawn his line in the sand here in Alabama and Mississippi. Where do you go from there?"
Santorum also is looking ahead to Illinois, which votes next week, and where polls show a tight race between him and Romney.
"I understand, you know, why he wants to continue -- Newt's got a lot of ideas and he certainly brings a lot to the table, but it's just right now what he's doing is out there attacking me, dividing the conservative vote and giving the, as he calls him, the 'moderate Massachusetts governor,' an easier role," Santorum said.
Another scenario being speculated on is what happens if none of the candidates has wrapped up the required 1,144 delegates entering this summer's convention.
In an interview Monday on Fox News, Romney said that would be catastrophic for Republicans.
"If we go to a convention, we would be signaling our doom in terms of replacing President Obama," he said, calling such a situation a "gift" to the incumbent commander-in-chief. "We need to select someone to become our nominee, get that person nominated and get focused on rebounding and getting (Obama) out of the White House."
CNN's John Helton, Gabriella Schwarz and Rachel Streitfeld contributed to this report.