The Republican presidential primary trudges on tonight. This time, it's in the Land of Lincoln, which pundits say is "must win" if former Massachusetts Gov. Mitt Romney wants to close out his nomination.

If you believe polls, Romney is poised for a win. The lastest poll, has Romney beating former Pennsylvania Sen. Rick Santorum by 15 points. A Ramussen poll from earlier this month had Romney up by 9.

Polls in the state close at 8 p.m. ET. We'll be live blogging all night, so make sure to refresh this page. If you're looking for live, county-by-county results, you'll find them here.

Update at 9:26 p.m. ET. Replacing A Law Professor:

Romney now makes the case that he his the man to make the American government leaner and less intrusive.

"I'm going to change that," he said. "We're going to get government out of the way."

Romney painted Obama as a law professor with no business experience and he offered himself as a "real choice and a new beginning." He said he had the "experience and the vision to get us out of this mess."

Update at 9:18 p.m. ET. 'What A Night':

"What a night," Romney says in his victory speech. "Thank you Illinois."

Romney congratulated his Republican opponents. But Romney very quickly pivoted to attack President Obama.

"It's time to say this word," said Romney. "Enough. We've had enough... We need a president who believes in us."

Update at 9:14 p.m. ET. 'Happy Anniversary':

Ann Romney takes the stage and gives her thanks to Romney. She says tomorrow is the couple's 43 wedding anniversary.

"Happy anniversary, sweetheart," she says.

Romney and his wife took the stage in Schaumburg, Ill., to raucous applause.

Update at 9:03 p.m. ET. The Delegate Count:

Illinois voters will actually vote on both the candidate and then select delegates who will represent them at the convention. Those delegates are labeled with the candidate they are supporting.

So, explains The New York Times' Nate Silver, the presidential preference ballot is technically a beauty contest. Silver reports on some of the delegate results:

"So far, 10 Congressional districts have reported a material amount of results in Illinois, all of them in the Chicago area. Mr. Romney's delegates lead the race in each one of these districts, which would account for 28 delegates total."

Update at 8:57 p.m. ET. What's Next?

The Hill reports on the next contest:

"The campaign moves to Louisiana, which holds its primary on Saturday. Romney has struggled in the Deep South, and a poll released by the Republican Magellan Strategies on Monday had Santorum leading Romney by 13 points in the state."

We're also waiting on speeches from the candidates. Santorum is in his home state of Pennsylvania and Romney is in Illinois.

Update at 8:49 p.m. ET. A Win Across The Board:

The New York Times, which is also calling the contest in favor of Romney, says this was an across-the-board win:

"Mr. Romney bested his chief rival among many types of voters, winning among men, women, and voters of all ages, the exit polls show. Mr. Romney drew the support of more moderate voters - as he has in the past - but also won among voters who said they were supportive of the Tea Party movement."

This win, the Times says, will give Romney some pretty solid ammunition to say that this primary contest must end in order to focus on the general election fight with President Obama.

Update at 8:43 p.m. ET. AP Projects Romney Wins:

The AP has now joined Fox and CNN projecting Romney will win Illinois. The wire service adds:

"Exit poll results show Romney was preferred by Illinois primary-goers who said the economy was the top issue in the campaign. The former Massachusetts governor also was overwhelmingly favored by those who said an ability to defeat President Barack Obama was the quality they most wanted in a GOP nominee."

Update at 8:41 p.m. ET. Fox News, CNN Project Romney Wins:

Based on exit polls and very early returns, CNN and Fox News are projecting that Mitt Romney will win Illinois.

Update at 8:25 p.m. ET. First Results Are In:

Results have started trickling in. With 0.6 percent of the precincts reporting, Romney has 54 percent of the vote and Santorum has 26.8 percent. Paul is in third place with 10.2 percent of the vote.

Update at 8:21 p.m. ET. The Experience Candidate:

The Washington Post's Chris Cillizza picks up on a shift in the race. He says Romney's "experience" argument - that he is the man with experience to turn this economy around - is working. Cillizza reports:

"Roughly one in five Illinois Republican voters said that a candidate having the right experience was the most important trait for them in deciding who to vote for. Of that group, Romney won 62 percent of the vote as compared to 19 percent for former House Speaker Newt Gingrich and just 8 percent for Santorum."

Previously, Gingrich had won that vote. Now that he's fading as a candidate, Romney, not Santorum, has picked up those voters.

Update at 8:11 p.m. ET. Romney's Campaign Spending:

The AP notes that as has been the case throughout this campaign, Romney has severely outspent Santorum:

"His campaign and Restore Our Future, a super political action committee that supports him, outspent Santorum and his super PAC by $3.5 million to $500,000, an advantage of 7-1."

Update at 8:07 p.m. ET. Illinois Up For Grabs?

Nate Silver, The New York Times' statistics wizard, says don't call the Land of Lincoln for Romney just yet. The notion that the state is up grabs, he writes, has some support in the exit polls:

"According to the exit poll, 32 percent of Illinois votes decided whom to vote for either just today or in the last few days. While that is not a spectacularly high figure, it is larger than in most other recent states."

CNN also couched its exit poll numbers saying the later waves of voters polled have tended to vote for Santorum.

Update at 8:01 p.m. ET. In Early Exit Polls, Romney Leads:

CNN reports the following early exit poll numbers:

— Romney: 45 percent

— Santorum: 35 percent

— Gingrich: 12 percent

— Paul: 8 percent

ABC News concurs, tweeting:

Breaking: ABC News exit poll analysis: Romney leads Santorum in Illinois Republican primary. Still too early to project winner.#ILPrimary

Update at 7:58 p.m. ET. Santorum Has A Lot Riding On Tonight:

CNN's David Gergen says tonight is a test for Santorum, especially, he said, after having a terrible week.

Santorum spent two days in Puerto Rico, only to get beat by Romney.

Update at 7:53 p.m. ET. Turn Out:

The Chicago Sun Times quotes Jim Allen, a spokesman for the Chicago Board of Elections Commissioners, as saying today's turnout was "extremely low."

"The turnout was heavier in Republican strongholds, where voters went to the polls knowing they would play an important role in the battle between Mitt Romney and Rick Santorum for the GOP presidential nomination," the paper reports.

Update at 7:43 p.m. ET. NPR's Delegate Count:

We've seen some questions on Twitter about NPR's delegate count. Indeed, it differs from other news organizations. Here's the why for that difference:

"NPR's delegate tracker awards only those delegates who are committed to voting for a candidate at the Republican National Convention through at least the first ballot. It does not estimate delegate allocation based on straw polls that frequently accompany early rounds of caucus events. Nor does it attempt to track preferences of 'unpledged' RNC members that by definition cannot be bound to a candidate. These guidelines distinguish it from delegate counts in other media."

The AP has the following count:

— Romney has 522 delegates.

— Santorum has 253.

— Gingrich has 135.

— Paul has 50.

Update at 7:37 p.m. ET. Exit Polls Show Big Suburban Turnout:

CNN reports on initial exit poll data:

"Exit polls showed more than 70% of the state's voters were from suburban areas, where Romney has done well in previous GOP contests. They also indicated Romney leading among more affluent and more educated voters, while Santorum led among rural voters and those who considered themselves 'very conservative.'"

Update at 7:19 p.m. ET. What's At Stake Tonight?

Our congressional editor S.V. Date tells us that 54 delegates are at stake tonight. "The state has 69 total," he says. "But 15 cannot be bound."

And, where do we stand so far? 771 delegates have been awarded and here's how that breaks down:

— Romney has 416.

— Santorum has 183.

— Newt Gingrich has 136.

— Ron Paul has 34.

The two that complete the math were awarded to Jon Huntsman before he exited the race.

Update at 7:02 p.m. ET. Ballot Problems:

Results may be slow to come tonight. The Washington Post reports that 25 of the state's 110 voting juridictions have ballots that are too wide to be fed through optical scanning machines.

"After the polls close this evening, workers will probably have to hand-trim the ballots - or hand count them," reports the Post.