President Barack Obama’s home state could be the jewel in Republicans’ crown this November, but much is riding on what happens in Tuesday’s Illinois primary.

Obama won by more than 15 percentage points in 2012 in the reliably blue state, but Republicans believe the Illinois governor’s mansion is within reach. Democratic Gov. Pat Quinn is facing dismal approval numbers, dragged down by the state’s basket-case economic and fiscal condition and an unpopular tax hike.

While a Republican win would only slightly shift the national map, the symbolism of the GOP taking over the state that launched Obama’s political career hasn’t escaped the attention of either party during the congressional midterm cycle.

On Tuesday, four Republicans are vying for the chance to unseat Quinn: billionaire businessman Bruce Rauner – the frontrunner and who many regard as the strongest candidate against the governor – state Sens. Bill Brady and Kirk Dillard, and state Treasurer Matt Rutherford. Quinn faces a longshot challenge from a former anti-gang organization director and is expected to win soundly.