For the first time since the 1988 primary between George Bush Sr. and Bob Dole, the GOP primary in Illinois matters. And while 54 of the state's 69 delegates are at stake, GOP candidates will be fighting for much more than delegates today. In the midst of a prolonged and at times agonizing 2012 Republican primary season, here are three reasons why the Illinois Primary matters:

1. Rick Santorum's Electability: While Rick Santorum has positioned himself as a viable threat to frontrunner Mitt Romney, he has yet to win in a state that is (a) reasonably assured to be competitive in the 2012 general election, and (b) not home to a sizable number of evangelical voters. Illinois professor and scholar Robert Bradley asks, "Can Santorum win a non-southern state where traditional business-oriented Republicans will be a large share of the voters in the primary?"

2. Mitt Romney's Momentum: With almost twice as many delegates as his closest rival, Rick Santorum, Mitt Romney hopes a win in Illinois today will widen the gap between him and his opponents. And while Romney has outspent Santorum 10 to one, the Republican party has refrained from coming together to support him. A win in Illinois, however, could provide Romney with the momentum he needs to push ahead as the clear frontrunner, and as the polls indicate, he has a good chance at winning. Former Illinois Governor explains, “Illinois politics are not driven by ideology, it’s more pragmatic," and because of Romney's experience in the business sector, voters in urban areas favor Romney. The main question will be voter turnout.

3. Obama's home state:  Representing the 13th district in the Illinois Senate from 1997-2004, Barack Obama received 45% of the vote in 2008's Illinois primary, and went on to win 62% of the Illinois vote against John McCain in the 2008 general election. The winner of today's primary, thus, will stand a much better chance against Obama come November, a point Santorum capitalized on in an election day speech in Illinois.

“Everyone says Illinois, Barack Obama’s home state, won’t have any impact on this election. You have a chance on Tuesday. You want to defeat Barack Obama. There’s only one guy in this race who can do it, and you need to make sure he wins Illinois on Tuesday.”

Going into today's primary, Mitt Romney holds a commanding lead in all Illinois polls, aggregated by the Huffington Post, with Public Policy Polling placing him 15 percentage points ahead of his main opponent in today's primary: Rick Santorum.