Mitt Romney crushed Rick Santorum in the Illinois primary Tuesday night, padding his delegate lead and once again forcing his Republican opponents to find another moment to mount a guerrilla challenge to his campaign. 
 
 With 55 percent of precincts reporting, Romney had 48 percent of the vote to Santorum’s 34 percent, Ron Paul’s 9 percent and Newt Gingrich’s 8 percent. That puts Illinois on track to be Romney’s biggest win in a large state since the Florida primary in January. 
 
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 While Santorum campaigned in Illinois and spent money there, an adviser to his campaign acknowledged even before the polls closed that the state was likely lost to Romney. 
 
 If Romney’s victory margin holds, it may prompt national Republicans to try more aggressively to conclude an already drawn-out primary season. And speaking to supporters in Schaumburg, Ill., Romney sought to cast the win as part of a national political tide in his direction. 
 
 “Hundreds of thousands of people have joined millions of people around the country to join our cause,” he said. “We know our future is brighter than these troubled times. We believe in America and we deserve a president who believes in us.” 
 
 Early exit polls pointed to a Romney-friendly electorate: 37 percent of voters said the top quality they wanted in a nominee was electability, according to CBS. Only 20 percent said their priority was finding a “true conservative.” 
 
 In a reflection of Romney’s perceived advantage, both Santorum and Gingrich spent primary day outside Illinois. Santorum plans to speak tonight from Gettysburg, Pa., while Gingrich has been campaigning in Louisiana ahead of Saturday’s primary there. 
 
 Only Romney was still in the Land of Lincoln, making a visit to Google’s Chicago office and holding an online event with Google+ users. 
 
 Asked if he expected to win the primary, Romney told a pool reporter: “Sure hope so.” 
 
 The race in Illinois played out in a now-familiar pattern: Romney’s conservative opponents charged into the state last week — in Santorum’s case, with some momentum from winning the March 13 primaries in Mississippi and Alabama. 
 
 But Romney’s financial advantage took its toll on his foes. Romney’s campaign and the super PAC Restore Our Future spent a combined $3.7 million on paid advertising in Illinois. Santorum’s campaign and super PAC spent just $532,000. In the populous, expensive Chicago media market, pro-Romney spending outstripped pro-Santorum spending by some $2 million. 
 
 “Fundraising is part of a campaign, so is organization,” said Romney spokeswoman Andrea Saul. 
 
 She added that complaints about Romney flooding the zone are “like a basketball team complaining that they lost to another team because their players are too tall.” 
 
 “That’s just ridiculous. This is all part of the game,” she said. 
 
 Santorum also lost airspeed in Illinois when he took a multi-day trip to campaign in Puerto Rico, where he lost to Romney in Sunday’s primary by a gigantic gap. 
 
 In the last 24 hours, the Illinois fight took a sharply confrontational turn after Santorum said at a campaign stop that he didn’t “care what the unemployment rate’s going to be” — a comment intended to convey that his whole campaign doesn’t rest on economic statistics. 
 
 “I want the unemployment rate to go down, but I’m saying my candidacy doesn’t hinge on whether the unemployment rate goes up and down,” he later clarified. ||||| Mitt Romney took a major stride toward the Republican presidential nomination Tuesday night, routing Rick Santorum in the Illinois primary for his third-straight big-state win and padding his already-formidable lead in the race for convention delegates. 
 
 Republican presidential candidate, former Pennsylvania Sen. Rick Santorum, stands with son Daniel and daughter Elizabeth as he speaks at his primary election night rally in Gettysburg, Pa., Tuesday, March... (Associated Press) 
 
 Republican presidential candidate, former Massachusetts Gov. Mitt Romney, right, kisses his wife Ann during a election night rally in Schaumburg, Ill., Tuesday, March 20, 2012. (AP Photo/Steven Senne) (Associated Press) 
 
 Republican presidential candidate, former Massachusetts Gov. Mitt Romney, right, and his wife Ann wave to a crowd in Schaumburg, Ill., after Romney won the Illinois Republican presidential primary, Tuesday,... (Associated Press) 
 
 Republican presidential candidate, former Pennsylvania Sen. Rick Santorum, speaks at his primary election night rally in Gettysburg, Pa., Tuesday, March 20, 2012. (AP Photo/Charles Dharapak) (Associated Press) 
 
 Republican presidential candidate, former Massachusetts Gov. Mitt Romney, right, and his wife Ann wave to a crowd during a election night rally in Schaumburg, Ill., Tuesday, March 20, 2012. (AP Photo/Steven... (Associated Press) 
 
 "What a night," Romney exulted to cheering supporters in suburban Chicago. Looking beyond his GOP rivals, he said he had a simple message for President Barack Obama, the man Republicans hope to defeat next fall: "Enough. We've had enough." 
 
 Returns from 61 percent of Illinois' precincts showed Romney gaining 48 percent of the vote compared to 34 percent for Santorum, 9 percent for Ron Paul and 8 percent for a fading Newt Gingrich. 
 
 That was a far more substantial showing for Romney than the grudging victories he eked out in the previous few weeks in Michigan and Ohio, primaries that did as much to raise questions about his ability to attract Republican support as to quell those questions. 
 
 Santorum, who hopes to rebound in next Saturday's Louisiana primary, sounded like anything but a defeated contender as he spoke to supporters in Gettysburg, Pa. He said he had outpolled Romney in downstate Illinois and the areas "that conservatives and Republicans populate. We're very happy about that and we're happy about the delegates we're going to get, too." 
 
 "Saddle up, like (Ronald) Reagan did in the cowboy movies," he urged his backers. 
 
 Romney triumphed in Illinois after benefitting from a crushing, 7-1 advantage in the television advertising wars, and as his chief rival struggled to overcome self-imposed political wounds in the marathon race to pick an opponent to Obama. 
 
 Most recently, Santorum backpedaled after saying on Monday that the economy wasn't the main issue of the campaign. "Occasionally you say some things where you wish you had a do-over," he said later. 
 
 Over the weekend, he was humbled in the Puerto Rico primary after saying that to qualify for statehood the island commonwealth should adopt English as an official language. 
 
 Initial results showed Romney's victory was worth at least 19 delegates in Illinois. 
 
 That gave him 541 in the overall count maintained by The Associated Press, out of 1,144 needed to win the nomination. Santorum has 253 delegates, Gingrich 135 and Paul 50. 
 
 Exit polls showed Romney preferred by primary goers who said the economy was the top issue in the campaign, and overwhelmingly favored by those who said an ability to defeat Obama was the quality they most wanted in a nominee. 
 
 While pre-primary polls taken several days ago in Illinois suggested a close race, Romney and Restore Our future, a super Pac that backs him, unleashed a barrage of campaign ads to erode Santorum's standing. One ad accused the former Pennsylvania senator of changing his principles while serving in Congress, while two others criticized him for voting to raise the debt limit, raise his own pay as a lawmaker and side with former Sen. Hillary Rodham Clinton to support legislation allowing felons the right to vote. 
 
 In all, Romney and Restore Our Future outspent Santorum and a super PAC that backs him by $3.5 million to $500,000, an advantage of 7-1. 
 
 In the long and grinding campaign, Santorum looked to rebound in next Saturday's primary in Louisiana, particularly given Romney's demonstrated difficulties winning in contests across the Deep South. 
 
 A 10-day break follows before Washington, D.C., Maryland and Wisconsin hold primaries on April 3. 
 
 Santorum is not on the ballot in the nation's capital. 
 
 Private polling shows Romney with an advantage in Maryland, and Restore Our Future launched a television ad campaign in the state during the day at a cost of more than $450,000. 
 
 Wisconsin shapes up as the next big test between Romney and Santorum, an industrial state next door to Illinois, but one where Republican politics have been roiled recently by a controversy involving a recall battle against the governor and some GOP state senators who supported legislation that was bitterly opposed by labor unions. 
 
 Already, Restore Our future has put down more than $2 million in television advertising across Wisconsin. Santorum has spent about $50,000 to answer. 
 
 Neither Newt Gingrich nor Ron Paul campaigned extensively in Illinois. 
 
 Gingrich has faded into near-irrelevance in the race, but he was defiant in a statement issued after Romney sealed his victory. 
 
 "To defeat Barack Obama, Republicans can't nominate a candidate who relies on outspending his opponents 7-1. Instead, we need a nominee who offers powerful solutions that hold the president accountable for his failures," it said. 
 
 Gingrich said his campaign will spend the time leading to the party convention "relentlessly taking the fight to President Obama." 
 
 Illinois fell into Romney's column far more easily than Michigan or Ohio had. 
 
 The night's vote count was plagued by ballot difficulties. Rupert Borgsmiller, executive director, of the Illinois State Board of Elections, said in late afternoon that 25 counties and the city of Aurora were affected by the ballot problem. He didn't know how many ballots were affected but said "clearly you can say more than hundreds." 
 
 Romney and Santorum campaigned energetically across the state, and not always in respectful tones. 
 
 "Senator Santorum has the same economic lightweight background the president has," Romney said at one point. "We're not going to replace an economic lightweight with another economic lightweight." 
 
 Santorum had a tart reply. "If Mitt Romney's an economic heavyweight, we're in trouble." 
 
 Anticipating a primary defeat, Santorum's campaign argued that the race for delegates is closer than it appears. 
 
 Santorum contends the Republican National Committee at the convention will force Florida and Arizona to allocate their delegates on a proportional basis instead of winner-take-all as the state GOP decided. Romney won both states. 
 
 On Tuesday, about four in 10 voters interviewed as they left their polling places said they were evangelical or born again. That's about half the percentage in last week's primary states of Alabama and Mississippi, where Santorum won narrowly. Despite an unusually lengthy race for the nomination, less than a third of those voting said in the polling-place survey they hoped the primary season would come to a quick end even if that meant their candidate might lose the nomination. 
 
 The findings came from preliminary results from the survey of 1,555 Illinois Republican voters, and had a margin of error of plus or minus 4 percentage points. The exit poll was conducted for The Associated Press and the television networks by Edison Research at 35 randomly selected polling places around the state. 
 
 As Illinois Republicans voted on Tuesday, Romney raised more than $1.3 million at a luncheon in Chicago. 
 
 Illinois was the 28th state to hold a primary or caucus in the selection of delegates to the nominating convention, about halfway through the calendar of a Republican campaign that has remained competitive longer than most. 
 
 A change in party rules to reduce the number of winner-take-all primaries has accounted for the duration of the race. But so has Romney's difficulty in securing the support of the most conservative of the GOP political base. Santorum and Gingrich have struggled to emerge as the front-runner's sole challenger from the right. 
 
 ___ 
 
 David Espo reported from Washington
– Rick Santorum has made it clear that he's sticking around despite his resounding defeat in Illinois. In a rambling election night speech in Gettysburg, he described this year's election as the most important since 1860, urged supporters to "saddle up, like Reagan did in the cowboy movies," and predicted a big win in Louisiana's primary on Saturday, reports the Washington Post. Speaking to Fox News, he blamed the Illinois loss on being outspent heavily in the Chicago media market, and said he didn't think super PACs should exist. In Chicago, "which has 70% of the population of the state of Illinois, we got outspent 21 to 1. We feel like we are up there, running against the machine,” he said, adding that Illinois is a moderate state that elects moderate Republicans. Romney won, he said, because of a super PAC funded by his billionaire friends. A Romney spokeswoman said Santorum complaining about being outspent was "like a basketball team complaining that they lost to another team because their players are too tall," Politico reports. "That’s just ridiculous," she said. "This is all part of the game."