Today is Super Tuesday, and 10 states stretching from Alaska to Virginia are holding crucial contests with over 400 delegates at stake.
Of the 10 states holding contests on Tuesday, Ohio is seen as the most important. It's partly symbolic because this state is such a major battleground in the general election. But for Rick Santorum, it's also critical because a loss here could finish his campaign.
Rick Santorum had been surging in Ohio, only to watch his lead in the polls slip away -- placing him in a last-minute dead heat with Mitt Romney.
While Santorum argued he's scrappy enough to claim Super Tuesday's biggest prize, Romney tried again to cast himself as the inevitable Republican nominee.
For help, he turned to his wife Ann, who spoke about her battles with multiple sclerosis and breast cancer on Fox News in an effort to humanize her husband, who's seen by some as an out of touch multimillionaire.
"You know, I don't even consider myself wealthy, which is an interesting thing. It can be here today, gone tomorrow," said Ann Romney.
But as the GOP field heads into Super Tuesday with 10 states and more than 400 delegates up for grabs, surveys say voters have developed largely unfavorable views of all remaining candidates.
A worry shared openly by Former First Lady Barbara Bush: "It's been, I think, the worst campaign that I have ever seen in my life. I just hate it. I hate the fact that people think compromise is a dirty word."
For better or for worse, no candidate will come out of Super Tuesday with enough delegates to claim the nomination. But if Mitt Romney wins in this state, the Republican voices calling for either Rick Santorum or Newt Gingrich to drop out will grow louder.