• County-by-county results from Illinois
• The real score in Illinois: Romney 41, Santorum 10
SCHAUMBURG, Ill. - Republican presidential contender Mitt Romney bolstered his front-runner status Tuesday with an easy victory over rival Rick Santorum in this crucial Midwestern state, padding his convention delegate count and helping to dampen conservatives' talk of a brokered party convention.
Unofficial results showed Romney dominating Santorum by double digits thanks in large part to Romney's overwhelming support among moderate voters in the Chicago suburbs who made up 70 percent of Tuesday's vote. In exit polls, Republicans said the ability to beat President Obama in the fall was the most important quality in their choice of candidate, a position that favored Romney.
Romney made no mention of Santorum in his victory speech, aiming exclusively at Obama. He did, however, make a pitch for Republicans reluctant to get behind him to do so now.
"Each day we move closer not just to victory but to a better America," Romney said. "Join us!"
Santorum retreated Tuesday to his home state of Pennsylvania, where he looked past the Illinois returns and vowed to fight on to Saturday's primary in Louisiana, the kind of conservative Southern state in which Santorum has consistently outperformed Romney.
Noting that he won southern and central Illinois, areas dominated by conservatives, Santorum said, "We're very happy about that and we're happy about the delegates we're going to get, too."
Romney and his supporters flooded Illinois with ads and robocalls, outspending Santorum at least 7-to-1. The decisive victory that spending earned for the former Massachusetts governor was a stark improvement over his showings in other Midwest battlegrounds, including Ohio and Michigan, where he only narrowly edged out Santorum.
With Romney expected to walk away with most of the 54 delegates at stake Tuesday -- with an additional 15 to be awarded in coming months -- the front-runner took an important step toward dampening rivals' talk of forcing Romney into a brokered convention this summer. Santorum didn't even qualify delegates for the ballot in four of Illinois' 18 congressional districts.
Voters in Illinois, where the unemployment rate exceeds the national average, said in exit polls that the economy was their top concern and for that reason many of them sided with Romney, a former businessman, whom they saw as more focused on creating jobs than Santorum.
Former House Speaker Newt Gingrich and Rep. Ron Paul of Texas remained in a tight battle for a distant third-place finish in Illinois.
Even as he marches closer to securing the nomination, Romney hasn't overcome criticism that he fails to excite the Republican base. Illinois Republicans, who rarely get the chance to cast a meaningful vote in a GOP presidential primary, didn't exactly jump at the opportunity to weigh in on the race, resulting in a fairly low turnout across the state.
Romney has not fared as well in more conservative states and has yet to win in the South, a region critical to any Republican presidential contender's chances of winning the White House.
But Romney said he likes his chances in a head-to-head battle with Obama in November.
"We're going to face a defining decision as a people," he said. "Our choice will not be one of party or personality. This election will be about principle."