Democratic House Speaker Michael Madigan says Republican Gov. Bruce Rauner's veto of a school funding bill is choosing "crisis over compromise."
Rauner used his amendatory veto powers to rewrite a bill that overhauls how the state distributes money to schools. Rauner objects to pension help and other money for Chicago Public Schools.
The move threatens whether all school districts statewide get money before school starts.
Madigan said in a statement that Democrats will continue to work with Republicans on a plan.
An update of the 20-year-old calculation Illinois uses to disperse funding to public schools is needed because the budget legislators approved last month calls for a new funding formula. There's wide agreement the current formula is unfair, but Republicans and Democrats disagree over how to change it.
The plan returns to the Legislature, where three-fifths majority votes are needed in each chamber to overrule or agree with the governor.