Chicago Public Schools asked a Cook County judge on Monday to fast-track the district’s civil rights lawsuit against the state of Illinois, warning of “devastating, immediate and irreparable harm” to students if a funding issue isn’t resolved quickly.

More than $100 million in the red, and on the hook for a $721 million teacher pension payment in June, CPS said it could cut the school year as short as June 1 if money doesn’t come through soon from the state. That’s 13 class days knocked off the end of Mayor Rahm Emanuel’s signature longer school year, which was scheduled to end on June 20.

The district recently filed a civil rights lawsuit against Gov. Bruce Rauner and the Illinois State Board of Education, alleging that the state’s ways of funding schools and pensions created “separate but unequal” schools systems in which CPS, whose students are predominantly poor and minority, get less money than their wealthier, white counterparts elsewhere in the state.

District officials are asking Judge Franklin Valderrama to issue a ruling before the end of April.

“There’s no question that ending school early is our worst-case scenario,” Claypool told reporters at CPS headquarters on Monday afternoon. “I want to be crystal clear: We believe it is possible to avoid ending the school year early, but only if Springfield acts or Judge Valderrama enjoins the state from distributing funding in a racially discriminatory manner.”

He wouldn’t say when officials will announce their decision.

But shortening the school year on top of four previously imposed furlough days may not even fully close the budget gap. In court documents, CPS estimated saving $91 million, and an additional $5 million from canceling summer school for elementary and middle-school general education students. Claypool called those estimates “conservative.”

Chopping off 13 days will push CPS’ school year below the state’s legal threshold, meaning that some state aid will be jeopardized, too. ISBE requires 180 class days for full funding and counts CPS as having four more days than required.

Claypool said CPS attorneys believe they have even more wiggle room.

The district still has to find or cut $129 million, the bulk of a $215 million gap left in December after Rauner vetoed a bill containing that money for teacher pensions. Rauner said the conditions to enact statewide pension reform that legislators had agreed to hadn’t been met.

In a prepared statement, Rauner’s education secretary, Beth Purvis, said, “As children statewide continue to be impacted by the state’s broken school funding formula, now is the time for CEO Claypool to engage in a constructive process to pass a balanced budget with changes that would help schools across the state, including those in Chicago.”

She was referring to ongoing state budget negotiations in the Legislature that may include the $215 million for CPS pensions.

Since the veto, school officials have scrambled to cut spending and have cut about $88 million so far in centrally provided training and school-based “freezes” CPS opted for instead of layoffs. So far they have not generated any new revenue.

They “froze” $46 million by taking half of what schools had left in discretionary spending accounts for recess monitors and after-school programs and classroom supplies, but were pressured into giving $15 million back to low-income schools after the Chicago Sun-Times revealed that they lost twice as much money as wealthier schools.

The furloughs that officials have already imposed coincide with staff training or planning days so children wouldn’t lose any school days. That measure, aimed at saving $35 million, provoked the Chicago Teachers Union, which accused CPS of targeting its mostly female membership with a pay cut.

CTU vice president Jesse Sharkey called the potential loss of three weeks of school “pretty devastating” for students and for his members who now face a 9 to 10 percent pay cut.

Sharkey renewed calls for the city to go after more revenue from a commuter tax or a tax on Chicago’s wealthiest citizens.

“We have the combination of a governor who doesn’t care about public education, and local leadership who have been unwilling to really fight for the kids on solutions that would tax the people who could afford it,” he said.

Emanuel had fought tooth and nail to extend the school year in 2012 from 170 days to 180. The extra time was a key reason teachers then walked out on strike.

Ald. Howard Brookins (21st), chairman of the City Council’s Education Committee, said closing CPS on June 1 would be untenable — and not simply because it would make a mockery of Emanuel’s vaunted longer school year.

“I would hate that it would come to this. Not that my kids won’t be jumping for joy that school is ending earlier. But parents won’t have been able to plan for this at the beginning of the school year, and it would be so disruptive for learning,” Brookins said.

“I admit that the last day or two of school are probably throwaway days for learning. They don’t do much instruction and the kids are not really focused. But to cut out nearly 20 days of school is untenable,” he said. “There’s got to be a way around it. I don’t believe the mayor will go along with it. If you were doing this on a straight business decision, it may make logical sense. But it doesn’t make good political sense. And it’s not in best interest of the children of Chicago.”

Chicago homeowners have already been hit with $837 million in property tax increases for police, fire and teacher pensions and school construction.

Brookins said he does not believe the City Council would be willing to go beyond that to stave off a shorter school year.

“I don’t know that the money would come fast enough,” even if there was the political will among aldermen to do more to help CPS, he said.