Illinois Democrats moved Tuesday to redraw Illinois’ Supreme Court districts in a maneuver aimed at cementing Democratic control on the state high court and establishing a legal backstop for the party’s legislative supermajorities.

But lawmakers from both parties still awaited redrawn congressional maps that will shrink the state’s 18-member U.S. House delegation by one, raising questions about whether those boundaries will emerge before the legislature’s scheduled Monday adjournment.

Over Republican wails of a naked power grab, Democrats released new court boundaries in hopes of recalibrating the court’s districts for the first time in 57 years. And while the GOP equated the move to “court-packing,” Democrats explained their push as an effort to address substantial population disparities in suburban and downstate judicial districts.

“This map is about equal representation in the state’s most important court,” Rep. Lisa Hernandez, chairwoman of the House Redistricting Committee, said in a statement that accompanied the new maps.

“As we strive for all to be equal before the law, we must ensure we all have an equal voice in choosing those who uphold it,” the Cicero Democrat said.

In a joint statement, she and state Sen. Omar Aquino, D-Chicago, noted that the existing Supreme Court district that covers DuPage, Kane, Lake, McHenry and a swath covering northwestern Illinois contains 3.2 million people, while districts elsewhere downstate contain less than 1.3 million residents.

“It’s time we make changes in recognition of the population changes and demographic shifts that have taken place since the 1960s,” Aquino, chair of the Senate Redistricting Committee, said in the statement.

Even though it maintains a traditionally lower profile in state government, the Supreme Court has played a pivotal role in the lives of every Illinoisan from wrongfully convicted killers to schoolchildren to retirees to the political class.

The court once established the legality of parking meters. Through a series of dramatic dissents in capital punishment cases, justices helped pave the way for the abolition of Illinois’ death penalty.

It ruled that government pensions are mostly sacrosanct. And it determined a challenge to the Chicago residency of Rahm Emanuel was frivolous, enabling him to run for mayor.

And in 2016, the court even got involved in the subject at hand — redistricting — by swatting down a voter referendum to change how the state draws political boundaries, a decision then GOP Gov. Bruce Rauner called “an affront to democracy.”

If Democrats vote on the plan and Democratic Gov. JB Pritzker approves it, it would represent the first effort at redrawing state Supreme Court boundaries since a failed Republican-led effort to do so in 1997. That move was stricken down by the state Supreme Court.

State Sen. Jason Barickman, R-Bloomington, called on Pritzker to veto the maps, referring to the Democratic governor’s campaign promise that he would overrule any map that is unfair.

“This is bigger than the governor keeping his word,” said Barickman, a potential rival to Pritzker in 2022’s election. “This is about showing the people of Illinois who have been so burdened by corruption and wrongdoing from their legislators that the next 10 years are going to be different.”

The existing Supreme Court boundaries, which have allowed Democrats to maintain a majority on the court for 52 straight years, have been in place since 1964 and were not changed when Illinois adopted a new state constitution in 1970.

Democrats, who hold a 4-3 majority on the court, controlled the state redistricting process in 2001 and 2011, as they do now, but opted against rejiggering the court’s boundaries both times as its majorities seemed stable.

This year, however, the party is staring down the possibility that its control of the court could be threatened significantly in 2022 after last fall’s loss of Democratic Justice Thomas Kilbride, of Rock Island, who lost his retention effort and his seat on the court. His loss came amid an onslaught of opposition funding, largely funded by Citadel CEO Ken Griffin, who contributed $4.5 million of his own fortune to Citizens for Judicial Fairness, which opposed Kilbride’s retention.

Kilbride’s former district stretches from Joliet to Peoria to the Quad Cities and is now represented by Democratic Justice Robert L. Carter. He is a temporary successor who has said he won’t seek election in 2022, making the seat a potential and even likely GOP pick-up on the court.

House Minority Leader Jim Durkin, R-Western Springs, was bracing for the new judicial maps when he accused Democrats Monday of preparing to stack the court. Kilbride’s loss sent a “shockwave” to the majority party’s major supporters such as trial attorneys and labor unions, Durkin said. “Quite frankly, if they don’t change that district, Republicans win and the balance of power will go to Republicans,” Durkin said. “That’s why there is going to be…some type of map that is going to redraw that third Supreme Court district to make it more appealing to Democrat voters.”

And that, effectively, is what Democrats did with their new map.

While partisan make-ups of the new judicial districts weren’t immediately available, Kilbride’s old district was recalibrated to include all of DuPage County, the state’s second most vote-rich county and one that has trended heavily Democratic in recent election cycles.

In last fall’s presidential election, for example, former Republican President Donald Trump lost to Democrat Joe Biden by 18 percentage points there. Democrat Hillary Clinton beat Trump in DuPage in 2016 by 14 percentage points.

Democrats also bolstered their fortunes by lopping off Republican counties in northwestern Illinois from the Supreme Court seat now held by Republican Justice Michael J. Burke.

Burke’s district, which had covered DuPage County, still includes a wide swath of Chicago’s collar counties, including Kane, Kendall, Lake and McHenry counties. Of those counties, only McHenry voted Republican in the last presidential campaign.

At a marathon hearing into the proposed maps Tuesday night, Republicans also expressed frustration with the lack of transparency about what data Democrats used to draw them.

Hernandez, the chairwoman of the committee, told them she didn’t know when the Democrats would be releasing the much-anticipated new boundaries for the state’s congressional districts.

“Once I know, I’ll give you a heads up,” she told GOP lawmakers.

Dave McKinney and Tony Arnold cover Illinois politics and government for WBEZ. Follow them on Twitter @davemckinney and @tonyjarnold.