Mitt Romney pulled out a narrow victory in the critical Super Tuesday battleground state of Ohio, giving the former Massachusetts governor an important boost after he and Rick Santorum divided up Republican primary votes and traded victories in states across the nation.
Santorum did not qualify for the ballot in three Ohio congressional districts, a failure that made it likely that Romney would win the delegate race in the state, no matter what happened with the popular vote.
But Santorum had been pushing to capture a majority of voters in the key swing state, which would have been a huge psychological victory for the former senator from Pennsylvania, who had already emerged as Romney's chief rival in the tumultuous Republican presidential primary fight.
After Santorum held the lead for most of the night, Romney was finally projected to be the victor after midnight. With 99.4 percent of precincts reporting, he held a 12,040 vote lead in Ohio, with 38 percent of the vote compared to Santorum's 37 percent. It was a come-from-behind win for Romney, who had trailed Santorum in Ohio polls until recent days.
The close contest in the Midwest culminated a dramatic political night in which Romney won Republican presidential primaries in Virginia, Vermont and Massachusetts, the state he served as governor, and was leading overwhelmingly in early returns in Idaho.
None of those victories were especially surprising. Polls had shown Romney winning comfortably in Vermont and Virginia, where only he and Texas Rep. Ron Paul had managed to get their names on the GOP ballot, and he has lived in Massachusetts for 40 years
Santorum snagged an important victory in Tennessee and also won Oklahoma and North Dakota. Newt Gingrich, meanwhile, boosted his struggling campaign with a victory in his home state of Georgia.
In, all ten states from Alaska to Massachusetts held primaries or caucuses on Tuesday, making it the most important day so far in the battle to select a Republican candidate to face President Obama in the November election. Results had yet to come in from Alaska.
It was Ohio, more than any other state, that may determine the long-term impact of this Super Tuesday.
For Romney, a victory in Ohio could be the best evidence yet that he is an inevitable nominee.
In the Buckeye State, exit polls showed Romney and Santorum splitting the Republican electorate along now familiar ideological and religious lines.
More than 70 percent of Santorum's votes in the state came from social conservatives, with more than half of his voters describing themselves as very conservative on social issues. Nearly six in 10 of Santorum's voters said Romney is insufficiently conservative. And in a sign of potential trouble ahead for the former Massachusetts governor, 57 percent of Santorum's backers in Ohio said they'd be dissatisfied with Romney as the nominee; 55 percent of Romney's supporters said the same about Santorum atop the GOP ticket.
Romney's competitive showing in Ohio, where he recently rebounded in polls after being significantly behind Santorum, was due in part to increased turnout among wealthier voters. About three in 10 voters reported having family income of $100,000 or more , with about half picking Romney. Santorum ran more evenly with Romney among voters without a college degree or income below $100,000.
Romney edged out Santorum among self-identified Republicans in Ohio, the exit polls showed. But the two candidates split more narrowly among independent voters. Romney and Santorum divided the conservative vote about evenly, with Santorum leading by a wide margin among the "very conservative" and Romney pushing back among "somewhat conservative" voters.