CHICAGO — His confidence surging, Mitt Romney pointedly ignored his Republican rivals on the eve of Tuesday's high-stakes primary election in Illinois and turned his fire instead on the Democrat he hopes to oust in the fall.
Romney pushed into President Barack Obama's home territory, assailing Obama's economic credentials on the Chicago campus where the president taught for more than a decade.
"Freedom is on the ballot this year," Romney told students and supporters, contending that the nation's recovery from recession was being limited by an "assault on our economic freedom" by Obama. "I am offering a real choice and a very different beginning," he said.
While Republican rival Rick Santorum courted anti-Romney conservatives across Illinois, the front-runner was trying to show he was more than ready to rise above the grinding GOP primary battle and move toward a general election matchup against Obama. Romney has secured more delegates than his opponents combined, and his nomination seems more assured each week as Santorum's shoestring campaign struggles under the weight of continued disorganization.
But a victory in Illinois' Tuesday primary is by no means assured.
Romney has spent big on advertising here, and he will have devoted more than three straight days to the state — an eternity by some standards in this constantly shifting campaign — by the time votes are counted Tuesday night.
After embarrassing Santorum with a one-sided victory in Puerto Rico Sunday, the Romney campaign sees in Illinois a potential breaking point for stubborn rivals who have defiantly vowed to stay in the race until the GOP's national convention in August. Should Santorum and Newt Gingrich stay politically alive until then and follow through on their threat, it could turn the convention into an intra-party fight for the first time since 1976.
Illinois is expected to be far closer than Puerto Rico's blowout, although recent polls suggest Romney may be pulling away. Even if he should lose the popular vote, Romney is poised to win the delegate battle. Santorum cannot win at least 10 of the state's 54 delegates available Tuesday because his campaign didn't file the necessary paperwork
Still, Santorum campaigned hard across the state Sunday and Monday in light of the stakes in Illinois, one of the last premier battlegrounds before the Republican race enters an extended lull after Saturday's contest in Louisiana.
"If we're able to come out of Illinois with a huge or surprise win, I guarantee you, I guarantee you that we will win this nomination," he said.
He rallied conservatives on Monday in Dixon, Ill., the hometown of President Ronald Reagan, saying, "I might add, just parenthetically, that if we just happen to win Illinois, that will be the 11th state that I've won."
He invoked the former president's insurgent campaign in 1976 against President Gerald Ford for the Republican nomination. Reagan lost, but it set the foundation for his return in 1980 when he won the nomination and defeated Democratic President Jimmy Carter.
As Romney focused on the economy in Chicago, Santorum said that the president's health care overhaul, not the economy, is the election's "most salient issue." And he continued to emphasize conservative cultural values: "Ronald Reagan understood that faith plus family equals freedom in America," Santorum said.
Romney, meanwhile, campaigned in the city where Obama taught law at the University of Chicago and where the president has his national campaign headquarters. Avoiding any reference to Republican opponents, Romney assailed the president.
"The American economy is fueled by freedom," he said, flanked by a row of American flags. "The Obama administration's assault on our economic freedom is the principal reason why the recovery has been so tepid — and why it couldn't meet their expectations, let alone ours."
At the current primary election rate, Romney would capture the nomination in June unless Santorum or Gingrich wins decisively in the coming contests. Including Puerto Rico's results, Romney has now collected 521 delegates, compared to Santorum's 253, Gingrich's 136 and Paul's 50, according to an Associated Press tally.
Romney and a growing number of Republicans across the country are eager to move beyond the increasingly nasty primary season that has consumed far more energy, resources and political capital than most expected. But the former Massachusetts governor has so far struggled to win over his party's most passionate voters — tea party activists and evangelicals who don't trust him as a true conservative.
Romney's wife, Ann, had called for Republicans to unite behind her husband at a campaign stop the night before, suggesting it was time to "move on to the next challenge."
Indeed, the battle for Illinois comes as Obama's campaign builds a mountain of campaign cash and organization in key states.
Obama collected $45 million for his re-election bid in February, accelerating his fundraising pace as his campaign fretted over an oncoming spending blitz by Republican-leaning outside groups.
With Republicans locked in their extended primary campaign, Obama's team is building a 50-state operation that aims to help register new voters, bring back past supporters and boost turnout. Obama's campaign had about $75 million in the bank through the end of January, but totals for February were not immediately available.
Romney and Santorum, by comparison, raised $11.5 million and $9 million respectively in February. And Romney and his allies are spending large amounts in Illinois.
Romney's campaign had spent $1.1 million, while the pro-Romney super PAC, Restore Our Future, had spent an additional $2.4 million on advertising in Illinois through Monday, according to figures collected by the media monitoring firm, SMG Delta. Santorum's super PAC, the Red White and Blue Fund, had spent $327,000, while his campaign had spent $200,000.
Each side bought television ads that attacked the other. And though Romney focused on Obama Monday, he had spent much of the previous week calling Santorum "an economic lightweight," an indication that he continues to view Santorum as a threat.
Associated Press writer Don Babwin in Rockford, Ill., contributed to this report.