The Illinois State Board of Education released numbers Wednesday showing how much state money most school districts could lose if lawmakers don't renew the 2011 income tax hike.
But Republicans say Democrats are proposing a doomsday budget scenario to try to raise support for keeping the tax rate where it's at. The 5 percent income tax rate is set to drop to 3.75 percent at the end of the year.
Democrats have emphasized the revenue the state is set to lose as a way to support Gov. Pat Quinn's push to keep the rate at 5 percent.
For many relatively wealthy suburban schools, less money from the state would mean a total drop in revenue of less than 1 percent.
Others that rely more on state money would get hit harder. Aurora East Unit District 131, for example, would lose about 5.5 percent, State Board of Education numbers show.
"You can't run away from the challenge that faces us," state Sen. Dan Kotowski, a Park Ridge Democrat, said. "This is a very conservative budget."
Republicans argue it doesn't have to be that bad.
State Sen. Matt Murphy, a Palatine Republican, accuses Democrats of picking "every worst-case scenario possible" to estimate how much money the state will make in order to build a case for extending the tax increase.
He argues different estimates would let lawmakers save schools from budget cuts.
"You can absolutely do that and have the tax rate roll back," Murphy told the Daily Herald editorial board Wednesday.
The dispute is likely to play out in the coming six weeks as lawmakers race to meet a May 31 budget deadline, with the question of whether lawmakers will extend the tax increase being a key one. They won't know how much money they have to spend for the year until that's decided.