The latest surveys of Illinois Republicans ought to put at least a bit of a damper on the growing speculation about a GOP stalemate leading to a brokered convention. The Fox Chicago News poll shows Mitt Romney holding onto a solid 37-31 percentage point lead over Rick Santorum in next Tuesday’s primary, with Newt Gingrich trailing badly at 14 percent. A new Rassmussen poll gives Romney an even bigger lead with a 41-32 percentage point lead with Gingrich also at 14 percent. Yet Romney, who is reportedly outspending Santorum in the state by a 5-1 margin, is taking no chances in Illinois. Nor should he. The Land of Lincoln may well be the last clear shot Santorum has to knock off the frontrunner in a major state where few thought he would have a chance to pull off an upset that could potentially alter the dynamic of the contest. Having narrowly failed to do so in Michigan and Ohio, Illinois is perhaps Santorum’s last opportunity on the primary calendar to show the party he can do more than just place a close second in a state where the GOP is not dominated by evangelicals.

Though Santorum, who has often outperformed his poll results (such as he did this past Tuesday in Mississippi and Alabama) is certainly still within striking range in Illinois, his biggest obstacle is not so much the deluge of Romney ad attacks (though that certainly doesn’t help his cause) as it is the decision of Newt Gingrich to stay in the race. Gingrich has spent the last couple of days promoting the idea that only by remaining on the ballot can Romney be denied the chance to gain a majority of the delegates before the convention. That’s a dubious notion that is being seconded by some Romney supporters seeking to stir the pot. But as in Michigan and Ohio, Gingrich’s only role is that of spoiler. Were he to get out now, it would give Santorum at the very least an extra few percentage points that may mean the difference between a stunning first place finish and another disappointing second place result that will have to be spun as a moral victory.

From the very beginning of the race, Romney has benefitted from a divided field that has enabled him to win victories he might never have achieved had he been left to face a single, credible conservative. It may be a matter of opinion whether Santorum qualifies as that person, but so long as Gingrich continues to muddy the conservative waters, it will be to Romney’s advantage.

Though observers are right to point out that Romney can ultimately win by piling up enough delegates even in states where he loses, the one real danger to his candidacy is for Santorum to rack up some upsets in states where he was thought to have no hope. Illinois is one such contest. Wisconsin, which is a winner-take-all primary in early April, is another. If Romney fails to win them, then he becomes prey to the sort of doubts that really could unravel his plans and lead to the brokered convention scenario that is a pundit’s fantasy and a GOP nightmare.

Gingrich may claim he is staying in to promote his “big ideas” agenda, but by allowing Romney to win a plurality in Illinois that he might not get without having another conservative in the race, Gingrich is sabotaging what might be Santorum’s last best chance to become the nominee. That is good news for Romney at a time when he needs to put together a winning streak that will convince his party he really is Mr. Inevitable.