Super Tuesday, the biggest single day in the GOP presidential nomination race, will be a key test for the remaining candidates and could give an indication about whether Mitt Romney is able to break away from his rivals. With three wins in a week, Romney has been riding a wave, but depending on how things shake out, the contest may not be over after this long day of voting.
In all, 419 delegates are up for grabs as 10 states hold primaries and caucuses - more than have been at stake in all the contests to date combined, and more than a third of the 1,144 delegates needed to clinch the nomination.
Georgia has the most delegates up for grabs Tuesday, but Ohio is the big prize because of its importance as a battleground state in the general election. Here's a guide on how things are shaping up:
Ohio is deemed a make-or-break state in the general election. It has voted for the winning presidential candidate in each of the past 12 elections.
What's at stake? Sixty-three of Ohio's 66 delegates are up for grabs in the primary. The remaining three are unpledged Republican National Committee delegates.
How close is the race? Strong support by Catholic voters in Ohio appears to be one reason why Romney is deadlocked with Rick Santorum, according to a survey released Monday.
A CNN/ORC International poll shows Romney and Santorum each grabbing 32% of likely GOP primary voters. Former House Speaker Newt Gingrich was at 14%, and Rep. Ron Paul of Texas was at 11%. Santorum had a lead in Ohio, but it seems to have evaporated. A Quinnipiac University survey Friday indicates that 35% of likely GOP primary voters in the Buckeye State say they back the former senator from Pennsylvania, with 31% supporting Romney. Santorum's four-point advantage is within the survey's sampling error.
"The surprise is that the Catholic candidate, Santorum, is losing the Catholic vote," says Keating Holland, CNN polling director. "Among Ohio Catholics who are likely to vote on Super Tuesday, 39% back Romney compared to 33% who support Santorum. Santorum has an advantage among Protestants by a 35%-to-29% margin."
Romney's advantage among Catholics is within the sampling error.
The political landscape: A look at the 2008 Ohio primary, which John McCain won over Paul and Mike Huckabee, shows how the conservative movement breaks down in the state. In that GOP primary, 65% said they were conservative, and 29% said they were moderate. The economy was the top issue then for voters and is likely to be the same again this year.
No doubt, Georgia has always been on Newt Gingrich's mind. But perhaps never more so than on this Super Tuesday. With the state having the most delegates to offer, and Gingrich needing a boost, a win is a must in his home state. CNN's Candy Crowley said she thinks Gingrich is likely to win big in Georgia.
"The good news for Gingrich is that no one else really made much of an effort there," Crowley wrote. "The bad news is that means Georgia won't be enough."
What's at stake? There are 76 delegates up for grabs in Georgia.
How close is the race? Gingrich represented the state's 6th Congressional District for 20 years. A Monday CNN poll indicates Gingrich is enjoying home-field advantage, with a 23-point lead over Romney. Gingrich is at 47% among likely GOP primary voters, with Romney at 24%, Santorum at 15% and Paul at 9%. Other recent surveys in Georgia also showed Gingrich with a double-digit lead.
Gingrich has said repeatedly over the past week that he needs to win the state. And he should. Two-thirds of people questioned in Georgia said they were definitely backing the candidate they are currently supporting, with three in 10 saying they may change their minds and 5% unsure or not supporting a candidate.
The political landscape: Republicans have gained big support from Georgia in presidential elections. In six of the past seven presidential contests, Republicans have won the state. In the 2008 primary, Huckabee won the state over McCain, who came in second, and Romney, who followed in third. In the 2008 GOP primary, 32% of voters described themselves as "very conservative."
Tennessee will help measure how well Romney can do in the South. CNN contributor Alex Castellanos argues that for Romney to be truly victorious on Super Tuesday he will have to lock up more than Ohio.
And perhaps, since Gingrich is expected to walk away with Georgia, Tennessee could be a good state for Romney, especially as Santorum's large lead dwindled going into Super Tuesday.
"Even a come-from-behind win in Ohio won't give Romney the momentum he needs to put this race away, but Romney could seal this deal Tuesday if he takes not only Ohio, but Tennessee," Castellanos said.
What's at stake? Fifty-five of the state's 58 delegates are up for grabs in the primary. The remaining three are unpledged RNC delegates.
How close is the race? An American Research Group survey released Sunday indicates that 35% of likely GOP primary voters in the state are backing Santorum, with 31% for Romney, 20% for Gingrich and 9% for Paul. Santorum's four-point advantage is within the poll's sampling error, which means it's basically all tied up.
Tennessee allows early voting, and the American Research Group survey indicates that Santorum has a 47%-35% lead over Romney among those who've voted early, with Gingrich at 11% and Paul at 7%.
"Although the 12 percentage-point early-vote lead for Santorum gives him a cushion, Romney is gaining among voters saying they will vote on Tuesday, and Santorum's early vote may not be enough to hold off Romney because Gingrich has gained strength at Santorum's expense," a statement from the research group said.
Tennessee holds an open primary, which means Republicans, independents and even Democrats can vote in the GOP presidential contest. According to the poll, Santorum has a seven-point lead over Romney among self-identified Republicans, with Romney holding a six-point advantage over Santorum among self-identified independents and Democrats.
So who is backing whom? The American Research Group survey indicates Santorum has a 43%-30% lead over Gingrich among people who say they are supporters of the tea party movement, with Romney at 17% and Paul at 5%. Among non-tea party supporters, Romney leads with 49%, followed by Santorum at 24%, Paul at 14% and Gingrich at 8%. Santorum has a nine-point advantage over Romney among men, with Romney holding a two-point lead over Santorum among women.
The political landscape: The state has a Democratic base in urban areas such as Memphis and Nashville, with nearby suburbs leaning Republican. Tennessee, however, has been a stronghold for Republicans in general elections. In 2008 McCain won the state by more than 15 points. In six of the past eight elections, the state has gone to the GOP. It's worth noting that in the 2008 GOP primary, Huckabee came in first among self-described conservatives, ahead of Romney and McCain.
In the 2008 primary, 73% of the GOP voters described themselves as "born-again" or "evangelical" Christians.
Santorum has said he thinks his viewpoint and brand of conservative values fit well with those of the red state of Oklahoma, and polls indicate that he may be right. But Romney has picked up a key endorsement from Sen. Tom Coburn that could swing some undecided voters to the ex-Massachusetts governor's side.
"This November, the most important choice facing the American people will be whether we will demand a solution and avert a debt crisis or whether we will continue to accept the status quo and hope for the best," Coburn wrote in The Oklahoman.
He followed by noting that in politics "choices are seldom perfect."
"But it is critically important to make a choice and support the person who is best equipped to solve the urgent problems before us. In my view, that person is Mitt Romney," Coburn added.
What's at stake? Forty of the state's 43 delegates are up for grabs. The remaining three are unpledged RNC delegates.
How close is the race? An American Research Group survey released Saturday indicates that 37% of likely GOP primary voters in Oklahoma back Santorum, with 26% for Romney, 22% for Gingrich and 9% for Paul.
So who is backing whom? According to the poll, Santorum leads by 15 points over Romney and Gingrich among men, and has a seven-point advantage over Romney among women. The survey indicates Santorum has a five-point advantage over Gingrich among those who say they are supporters of the tea party movement, and an eight-point one over Romney among those who say they are not tea party supporters.
The political landscape: This previously Democratic-leaning state has begun to trend toward Republicans. In the 2008 general election, McCain won all 77 counties. Seventy-three percent of voters in the 2008 primary said they were conservative. Of those conservatives, Romney placed third in 2008, garnering 26% of the vote behind Huckabee and McCain. In that primary, 72% of voters described themselves as "born-again" or "evangelical."