Illinois Senate Democrats plan to introduce a school funding bill on Wednesday that offers no revenue source for a revamped formula that would ultimately shift money from wealthier districts to the poorer ones over a four-year phase-in.

Gov. Bruce Rauner — who is deadlocked with Democratic leaders over the state’s budget — hasn’t closed the door on the proposal — at least not yet.

The Republican governor has said the state’s priority this year should be to fully fund education to the foundation level — the minimum per-pupil amount set by law. But Rauner aides say the governor will carefully review Sen. Andy Manar’s bill. Rauner has also complained that the state’s current funding formula relies to heavily on local property taxes to fund schools and that state money should be allocated proportionately for lower income districts and rural districts.

Manar’s plan, which the Democrat from downstate Bunker Hill plans to introduce in the Illinois Senate on Wednesday, would cost about $600 million — an estimated $400 million in the first year to ensure school districts don’t initially lose money, as well as $200 million for the state to pay normal costs of Chicago teacher pensions.

State Democrats say no funding sources were identified in last year’s school budget, but schools still opened on time, and the budget boosted funds for K-12 education by more than $250 million.

“What was the funding source for the bill he [Rauner] signed that raised K-12 education spending? The answer is this is the priority, in my mind,” Manar said “Let’s figure out what the cost is. Let’s begin there. Let’s get that bill passed. Let’s get it signed into law. Let’s not wait until May 31. Let’s move forward so that this uncertainty can get behind us, and we an begin what is going to be an effort that is going to take several years to reverse the trend.”

Calling the formula a “statewide solution to a statewide problem,” Manar said the bill — actually an amendment to Senate Bill 231 — is based in part on a bipartisan report from 2014.

“Everything in this bill is intended to take steps toward parity, toward a system that is statewide in nature that doesn’t treat different school districts in different ways utilizing $13 billion of state resources,” Manar said.

The big changes would include a shift in the state aid formula, reducing the role of local property taxes in favor of state funding. Manar’s proposal seeks to target state dollars to schools where the dollars can produce the biggest academic turnaround among students. That includes schools with high poverty levels, students with disabilities and children learning English as a second language.

Currently, some schools in Illinois are able to spend as much as $30,000 per student, while others can only afford the $6,119 foundation level.

Under Manar’s proposal, money would be shifted from wealthier school districts to poorer ones. But there would be a cap on any losses to a school district at no more than $1,000 per student per year. The formula would allow for wealthier districts to buy some time to budget and plan for the years ahead, while not losing money in the first year.

How will the funding formula affect Chicago? Chicago Public Schools won’t get special block grants, but the district would get about $200 million for pension costs plus an additional $100 million in state aid.

CPS said it will be reviewing Manar’s bill and agreed with his claims about funding inequity across the state.

“As Senator Manar rightly pointed out, the way Illinois funds education is the least equitable in the country, and unfairly punishes our poorest children. In Chicago, that means our lowest income children – many of them minorities – aren’t getting adequate funding for their education, and we’ve been pushing for Springfield to make this right,” CPS spokeswoman Emily Bittner said in a statement.  “We look forward to carefully reviewing the details of this measure because we know that all of us – Springfield, teachers and Chicago taxpayers – must be part of solving CPS’ budget crisis.”

Although the bill is designed so that no school districts would lose money within the first year, that will cost the state an estimated $400 million — the final figures being worked out by the Illinois State Board of Education. Losses to the wealthier districts would be phased in over three more years.

Rauner has said he won’t support any education funding formula in which any districts lose money. He has proposed an extra $55 million to fully fund schools to the state’s $6,119 minimum per student.

“Changing the formula is going to be hard. If it were easy, it would have been done already,” Rauner said Tuesday. “What we can’t do is have a system where we pit school districts against each other. We have got to come up with a way to significantly increase funding and focus it on the lower-income districts and rural districts that don’t have the resources. That’s the more fair way to do it.”