It appears that when Rick Santorum steps to the lectern in Cape Girardeau on Saturday night, he will still be solidly in the running as a potential GOP challenger for Democratic President Barack Obama.

While Mitt Romney squeezed out a win in pivotal Ohio, captured four other states with ease and padded his delegate lead in the race for the Republican presidential nomination, he was forced to share the Super Tuesday spotlight with Rick Santorum, who won three states.

Newt Gingrich won a home-field primary in Georgia.

If Santorum, a former senator from Pennsylvania, had lost big Tuesday, he may have spoken at Saturday's Lincoln Day event struggling to maintain credibility as a legitimate threat to Romney.

"I would think he did better than some of the pundits thought he was going to do," said Evan Trump, the chairman of the Cape Girardeau County GOP. "The pundits out there believed that Romney was going to take most of the states except for Gingrich taking Georgia."

Santorum's wins will mean he'll bring more excitement to Cape Girardeau, where he is scheduled to speak at 7 p.m. at Ray's Plaza Conference Center, where 700 people have bought tickets to hear his conservative message. It also may help him the following week, when Missouri holds its caucuses for the state's 52 delegates.

But first he had to get through Super Tuesday.

Santorum broke through in primaries in Oklahoma and Tennessee and in the North Dakota caucuses. Mitt Romney had a home-state win in Massachusetts to go with victories in Vermont and Virginia. . He added the Idaho caucuses to his column.

Ohio was the marquee matchup of the night, a second industrial state showdown in as many weeks for the two rivals. Of all the Super Tuesday states, it drew the most campaigning and television advertisements, and for good reason -- no Republican has ever won the White House without carrying the state in the fall.

With votes tallied in 99 percent of the state's precincts, Romney led Santorum by about 12,000 votes out of 1.1 million cast.

Romney said, "This is a process of gathering enough delegates to become the nominee, and I think we're on track to have that happen."

But Santorum's showing on top of Gingrich's triumph was fresh evidence that Romney's rivals retain the ability to outpace him in parts of the country despite his huge organizational and financial advantages.

Santorum waited until Oklahoma and Tennessee fell into his column before speaking to cheering supporters in Ohio.

"We're going to win a few. We're going to lose a few. But as it looks right now, we're going to get a couple of gold medals and a whole passel of silver," he said.

There were primaries in Virginia, Vermont, Ohio, Massachusetts, Georgia, Tennessee and Oklahoma. Caucuses in North Dakota, Idaho and Alaska rounded out the calendar. In all, 419 delegates were at stake in the 10 states, and Romney's wins, by overwhelming margins, allowed him to pad his earlier lead for the nomination.

Romney picked up at least 183 of the 419 Super Tuesday delegates at stake. Santorum gained at least 64, Gingrich 52 and Rep. Ron Paul at least 15.

That gave the former Massachusetts governor 386, more than all his rivals combined, a total that included endorsements from members of the Republican National Committee who automatically attend the convention and can support any candidate they choose. Santorum had 156 delegates, Gingrich 85 and Paul 40. It takes 1,144 delegates to win the nomination at the Republican National Convention in Tampa, Fla., this summer.

In interviews as voters left their polling places, Republicans in state after state said the economy was the top issue and an ability to defeat Obama was what mattered most as they made their Super Tuesday choices.

They also indicated nagging concerns about the candidate they supported, even in Massachusetts, There, one-third of all primary voters said they had reservations, and about three-quarters of those voted for Romney.

Massachusetts is a reliably Democratic state in most presidential elections, but in Ohio, 41 percent of primary voters said they, too, had reservations about the candidate they supported. No Republican has ever won the White House without capturing Ohio.

Gingrich's victory was his first since he captured the South Carolina primary on Jan. 21, and the former House speaker said it would propel him on yet another comeback in a race where he has faded badly over the past six weeks.

Obama, the man they hope to defeat in November, dismissed the almost-constant criticism of his foreign policy efforts and accused Republicans of "beating the drums of war" over Iran. "Those folks don't have a lot of responsibilities. They're not commander in chief," he said. Unopposed for the Democratic nomination to a second term, he stepped into the Republican race with a Super Tuesday news conference at the White House, then attended a $35,800-a-ticket fundraiser a few blocks from the White House.

Ohio was the day's biggest prize in political significance, a heavily populated industrial state that tested Santorum's ability to challenge Romney in a traditional fall battleground. Georgia, Gingrich's home political field, outranked them all in the number of delegates at stake, with 76, a total that reflected a reliable Republican voting pattern as well as population.

Romney, the leader in the early delegate chase, flew to Massachusetts to vote and said he hoped for a good home-state win.

He also took issue with Obama, saying, "I think all of us are being pretty serious" about Iran and its possible attempt to develop nuclear weapons.

Gingrich effectively acknowledged he had scant Super Tuesday prospects outside Georgia, where he launched his political career nearly three decades ago. Instead, he was pointing to primaries next week in Alabama and Mississippi, and he told an audience, "With your help, by the end of next week we could really be in a totally new race."

The polls show the president's chances for re-election have improved in recent months, as the economy has strengthened, unemployment has slowly declined and Republicans have ripped into one another in the most tumultuous nominating campaign the party has endured since 1976.

Staff writer Scott Moyers contributed to this report.