Illinois Senate Democrats are predicting grim consequences for schools if the scheduled rollback of state income tax rates goes into effect next year.

In all, school districts would lose more than $450 million in general state aid funding next fiscal year, according to data released by Senate President John Cullerton’s office Wednesday.

Chicago Public Schools would lose almost $174 million, according to the data.

State Sen. Dan Kotowski, D-Park Ridge, called the numbers a “conservative and realistic scenario.”

“It’s going to have a major impact on the lives of students and the people who educate them,” he said.

The state income tax rollback has been a contentious issue.

Gov. Pat Quinn ended months of dancing around the income tax question last month and said he would push for a permanent extension of the temporary 67 percent hike he enacted in 2011 to help pare a multi-billion-dollar backlog of unpaid bills and pay increasing state pension obligations.

On Wednesday, after Democrats released their data, Senate Republicans shot back.

“We don’t believe the scenario they’ve created — that without an extension of their 67 percent income-tax increase the state budget will collapse,” said Patty Schuh, spokeswoman for Senate Republican leader Christine Radogno. “We don’t buy into that scenario. We believe they are attempting to create a crisis to justify going back to taxpayer’s pockets.”

Schuh said Democrats “have not made education a priority” the past ten years they’ve run the Statehouse.

“The Democrats have chosen to spend taxpayers money in other areas, so who would believe now that education would be a priority?” she said. “These are the same people that told us their income tax increase would be temporary. Now they say it will be permanent. They told us their income tax increase would pay the bills get us out of debt and fix the state budget. Now they’re telling us ‘No, we have big problems.’ Who believes them?”

Katie Hickey, a Quinn spokeswoman, said “if nothing is done, Illinois will face extreme and radical cuts to education and we don’t think that’s the way to go. … The state is at a turning point and now is not the time to turn back on the progress being made.”

Meanwhile, Chicago’s top schools official said CPS “cannot support any further cuts to our children and their classrooms.  

“CPS has cut its bureaucracy and directed resources towards the classroom, which is yielding measurable, meaningful results for our students. Further state budget cuts will jeopardize that progress and have a detrimental impact on our children,” CPS CEO Barbara Byrd-Bennett said in a statement.

Contributing: Dave McKinney