Voters in 10 U.S. states are going to the polls for "Super Tuesday" nominating contests in the biggest day of voting yet in the race to choose the Republican Party's presidential nominee.
A total of 419 delegates are up for grabs Tuesday, more than a third of the 1,144 delegates needed to win the Republican nomination. The number of delegates available from the Super Tuesday races are more than all the previous primaries and caucuses combined.
Frontrunner Mitt Romney, who has won the last five states, hopes to use the contests to establish himself as the inevitable nominee. His main rival, social conservative Rick Santorum, is attempting to regain the momentum that helped him win three states in one day in early February.
On Monday, Romney and Santorum campaigned for support in the closely watched midwestern "battleground" state of Ohio, where the two are locked in a tight race.
Ohio voters Tuesday expressed their backing of both candidates.
"I like the guy," said Bob Head, a voter supporting Mitt Romney. "He's not necessarily my favorite candidate on all issues, but quite frankly, I think he's the most likely to be able to beat Obama in the general election."
"Essentially, I think he [Santorum] can beat [President Barack] Obama and I think he's got the answer for the future of America," said Tom Lewis, a voter supporting Rick Santorum.
A new Quinnipiac University survey shows Romney, a former governor of Massachusetts, has gained momentum since last week and now has 34 percent of likely Republican primary voters in Ohio, three points ahead of former Pennsylvania Senator Santorum, who led in Ohio late last month.
Tuesday's contests will move Republicans closer to selecting their candidate to face President Barack Obama, a Democrat, in the November election.
Georgia, Massachusetts, Vermont, Virginia, Oklahoma and Tennessee are the other states holding primaries on Tuesday. There are caucuses in Idaho, North Dakota and Alaska.
The other two candidates vying for the Republican nomination are former House of Representatives speaker Newt Gingrich and Texas Congressman Ron Paul.
Gingrich campaigned Monday in Tennessee and is confident of a win in Georgia, the state he represented in Congress for two decades and where polls show he has a large lead.
Paul, who has yet to win a nominating contest, hopes to do well in Alaska, Idaho and North Dakota.
Romney is expected to do well in Massachusetts, where he served as governor from 2003 to 2007, and in the neighboring state of Vermont, as well as in Virginia, where only he and Paul are on the ballot.
Meanwhile, President Obama, whose approval ratings have gradually been improving, hopes to gain attention on Tuesday with an afternoon news conference.
**As of March 4, 2012