(CBS News) SMYRNA, Ga. - It's "Super Tuesday," when more Republican convention delegates will be awarded than in all the previous contests combined. More than 400 delegates, in ten states, are up for grabs.
The stakes are huge. If Mitt Romney wins big across the ten states, it could help seal the deal as he tries to become the GOP presidential nominee. But if he doesn't, the race could go on for months.
Romney spent Monday insisting he's the only candidate focusing on the issues that matter most. "I look at this campaign right now," he said, "and I see a lot of folks all talking about lots of things, but what we need to talk about to defeat Barack Obama is getting good jobs and scaling back the size of government, and that's what I do."
Romney already has 187 delegates. There are 419 more up for grabs today -- more than a-third of the total needed to win the Republican nod.
The key battleground between Romney and Rick Santorum, with 63 delegates up for grabs, is Ohio.
Both candidates spent the final day campaigning there -- Romney was trailing in the polls there just days ago but, after a recent surge, it's now a virtual dead heat.
Santorum says, for better or worse, Ohio could be a turning point in his campaign. "While it may not be make-or-break," he says, "it's going to be a huge, huge deal."
Though he was leading national polls for most of February, Santorum is painting himself as the underdog -- the little guy against a massive machine. "Give credit to Governor Romney and what he's been able to put together -- amassing an enormous amount of money," Santorum says. "But this race isn't going to be won or lost in the fall on money."
Meanwhile, Newt Gingrich is hanging his hopes on Georgia, his home state, which would be his first win in six weeks. He had said a loss here could end his campaign -- but now says he's confident that won't happen.
"It looks now," Gingrich maintained, "like, in Georgia, we will carry the state by four or five times the margin that Romney had in Michigan (where Romney grew up), so that feels pretty good."
Both Gingrich and Santorum are confidently predicting they'll stay in this race all the way to the Republican convention in August.
To see Chip Reid's report, click on the video in the layer above.