A version of this story was first posted by member station WBEZ.

State money to public schools across Illinois could be cut off due to yet another budget impasse between lawmakers and Gov. Bruce Rauner.

On Tuesday, Rauner, a Republican, partially vetoed a bill to overhaul the state's school funding formula, denouncing it a "bailout" of Chicago Public Schools.

"With my changes, Illinois can achieve historic education funding reform that is fair and equitable to all Illinois children," Rauner said from the state Capitol in announcing his veto.

Rauner's veto comes less than a month after the resolution of a two-year standoff between the governor and the legislature that left the state without a permanent budget and with billions of dollars of unpaid bills.

Rauner, who faces re-election in 2018 in a heavily-Democratic state, recently reshuffled the governor's office and has hired aides from a conservative think thank who have been waging political combat with Democrats.

Chicago Mayor Rahm Emanuel, a Democrat, quickly criticized Rauner, saying in a statement that "his math is fuzzy, his claims have been proven false and the only thing the governor's action advances is his own personal brand of cynical politics."

Schools are scheduled to receive their first state payments on Aug. 10. While districts across Illinois have said they will open on time, some have said they'll be forced to borrow money or make cuts, and they warn of more dire circumstances if a funding bill is not passed. School districts that rely most heavily on state aid because they lack a strong property tax base are most in danger; some have said their local property tax funds will only last until Halloween.

The bill now heads back to the Democrat-controlled state legislature, which will have to choose whether to accept or reject Rauner's changes or do nothing, which would kill the bill. There is no backup plan to distribute nearly all the state's education funding before the academic year starts if Democratic leaders in the House and Senate do not have enough votes to override Rauner's veto.

In recent weeks, Rauner has said he supports the overall funding formula, but accused Democrats of inserting extra money for CPS' underfunded pension system. Senate President John Cullerton, a Democrat, has bristled at the governor's characterization of the bill as a CPS "bailout," accusing Rauner of pitting the rest of the state against Chicago.

Cullerton has argued that Chicago's schools have been treated unfairly by the state for decades, and that the measure also includes more money for suburban and downstate teacher pensions. The original version of the bill received support from superintendents and independent education policy groups.

In a display of how contentious state politics has become, Cullerton recently questioned Rauner's "mental state" for promising to partially veto the bill. That prompted Rauner's mental health director to accuse Cullerton of perpetuating the stigma attached to mental illness.

It's not yet clear whether Democrats have the votes to override Rauner's veto.

Illinois is still cleaning up the fiscal mess left by a recently resolved state budget standoff that lasted two years.

Universities and social services received sporadic funding from the state in that time, forcing them to reduce staff and cut programs, while the state's bond ratings took several hits. A state budget was approved last month after bond-rating agencies threatened to downgrade the state's credit rating to junk status.

But even then, a budget was approved not because of an agreement between Rauner and Democratic legislative leaders, but because 11 Republicans broke from Rauner to vote in favor of a spending plan that included an income-tax increase.

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