Mitt Romney today regained some of his footing as the leader of the Republican race for the presidential nomination, as he decisively beat Rick Santorum in the Illinois primary.
About an hour after the polls closed at 8 p.m. ET, Romney led his main rival by nearly double the number of votes, with almost one-third of precincts reporting.
Exit polls showed voters siding with Romney on key issues like electability and empathy. ABC News projected Romney would win based on those polls and vote tallies that had been reported.
Exit polls also showed Romney winning thanks to two groups of voters: people in households with incomes of more than $100,000, and college graduates. He beat Santorum by 25 points among the first group and by 18 points among degree holders.
In a victory speech in Illinois just over an hour after polls closed, Romney called his win an "extraordinary victory." He also congratulated "my fellow candidates on a hard-fought contest here."
That was the only mention of his opponents. Romney's speech was fixated squarely on President Obama, particularly his background in Chicago, near the site of Romney's speech.
"For 25 years, I lived and breathed business and the economy and jobs," he said. "I had successes and failures. But each step of the way, I learned a little bit more about what makes our American system so powerful. You can't learn that teaching constitutional law at the University of Chicago, all right? You can't even learn that as a community organizer. The simple truth is that this president doesn't understand the genius of America's economy or the secret of the American economic success story. The American economy is fueled by freedom."
Romney has won more states and more delegates than has any other candidate in the GOP primary, but he has struggled to sustain a narrative of an undisputed front-runner.
All of Romney's opponents have questioned his strength because of his apparent weakness with the conservatives who have voted in the primaries so far, and they have vowed to stay in the contest until the party's summer convention.
Even Romney's win in Illinois tonight cost him. He and the super PAC supporting him outspent Santorum's forces by an eight-to-one margin on campaign advertising.
Santorum, who needed a significant showing in Illinois to prove that he can gain support in areas that aren't just socially and religiously conservative, told supporters in his home state of Pennsylvania that he was "going to win" central, western and "downstate" Illinois.
"We won the areas that conservatives and Republicans populate, and we're happy about that," Santorum said in his speech after Romney's. "We're happy about the delegates we're going to get, too."
Romney is set to win most of the 69 delegates at stake in Illinois. Santorum didn't even qualify for the ballot in four of the 18 congressional districts in the state, making him ineligible for 10 of those delegates.
After Santorum won a string of primaries in southern states by winning over social conservatives and religious voters, Romney's campaign has shifted its storyline to argue that the former Massachusetts governor is the only candidate who can mathematically win the nomination by getting 1,144 delegates.
The other candidates, meanwhile, continue to insist that they are the only ones who can beat Obama in a general election.
Santorum took shots at Romney in his primary-night speech, arguing that "we don't need a manager" as president, alluding to the former governor's job at the private-equity firm Bain Capital.
"It's great to have Wall Street experience," he said. "I don't have Wall Street experience, but I have experience growing up in a small town in western Pennsylvania."
Exit polls from Illinois found that six in 10 voters, who were typically less ideological than Republicans in the states Romney has lost, said Romney had the best chance of beating Obama. The front-runner also led Santorum narrowly as the candidate who voters said understands their problems the best.
Romney, who told his supporters that Obama has prevented the country from leading the world in manufacturing and accused him of general American dream-crushing, said in his speech that "when we replace a law professor with a conservative businessman as president, that's going to end."
"The economy is struggling because the government is too big," he said. "Each day we move closer, not just to victory, but to a better America."
Romney badly needed to win big in Illinois to deny Santorum the momentum he has gained as he added southern states to his win column, most recently Alabama and Mississippi a week ago.
Gallup reported as Illinoisans voted that Romney's lead over Santorum nationally was 34 percent to 30 percent, though the former Pennsylvania senator is still the preferred choice among conservatives and Midwestern voters. That national measure has also swung back and forth like a heavy pendulum; in the middle of February, for example, Santorum led Romney by 10 points.