More than three years after the state’s legislative map became law and after two election cycles during which it was in effect, Illinois House Republicans on Tuesday asked the state Supreme Court to declare the Democratic mapping effort an unconstitutional political gerrymandering that unfairly limits the choices of voters.

In their lawsuit, Republicans argued the boundaries drawn to give Democrats supermajorities in the state House and Senate are in violation of both the state constitution’s mandate that elections be “free and equal” and a requirement that districts be drawn compactly.

The legislative boundaries enacted into state law in September 2021 were “drawn with the primary motivation to ensure Democrat victories and is anything but ‘free and equal,’ ” the lawsuit argues. “The Enacted Plan thus denies voters their equal right to participate in the political process and to elect representatives of their choice.”

During a news conference on Tuesday, House Republican Leader Tony McCombie, the lead plaintiff in the lawsuit, called the map “not just a little corrupt. It may be one of the most corrupt in American history.”

“Illinois House Republicans refuse to stand by while Democrats rig elections and manipulate the system to maintain their grip on power,” she told reporters. “It is time to expose this for what it really is — cheating.”

Jon Maxson, spokesperson for Democratic House Speaker Emanuel “Chris” Welch, contended McCombie’s suit was an attempt to distract the public from Republican President Donald Trump’s “unlawful attempt to slash services working families need” by “relitigating a matter that courts decided years ago.”

There was no immediate reaction from Democratic Attorney General Kwame Raoul, whose office would be charged with defending the maps as a matter of state law.

Republicans, joined by minority voting advocacy groups, were ultimately unsuccessful in a previous federal court challenge alleging federal Voting Rights Act violations in some Democratic drawn districts. But because the U.S. Supreme Court has declared that partisan gerrymandering is not a valid issue to be adjudicated in federal courts, the GOP is bringing the case to the Illinois Supreme Court.

In doing so, Republicans are asking the lawsuit to be decided by a court that has a 5-2 majority of Democratic justices.

Under the legislative boundaries used in elections in 2022 and last November, Democrats gained and maintained a 78-40 majority over Republicans in the state House and a 40-19 advantage in the state Senate.

In their lawsuit, House Republicans try to use their results to bolster the case. The lawsuit says GOP candidates for the state House won 50.9% of the votes cast in all House races statewide in 2022 but won only about one-third of the seats at stake. In 2024, Democrats won 55% of the statewide House votes but won two-thirds of the 118 seats at stake, according to the lawsuit.

“With this level of entrenched dominance, it is unsurprising that almost half (54 of 118) of the state House elections in 2024 were uncontested,” the lawsuit said.

The lawsuit notes that the state constitution requires that all elections be “free and equal.” But under the legislative map as enacted, “that is an impossibility,” the lawsuit argues. The constitution also “requires that all ‘Legislative Districts shall be compact.’ But the (map) subordinates compactness to the partisan and incumbent-protection goals of the majority political party.”

In the lawsuit, House Republicans accused Democrats of diluting GOP voting strength by placing Republican voters into Democratic-majority districts, many of them Black majority districts.

“The General Assembly’s goal is evident: Draw skinny Democratic districts that snake into Republican areas and absorb as many Republican votes as possible without jeopardizing Democrats’ ability to win those districts,” the suit alleged. “The General Assembly is using Black-majority districts to crack Republican votes solely for partisan purposes.”

Using a 1981 ruling over a legislative district that was struck down by the state Supreme Court for violating the compactness requirement, the House GOP contends 52 current district boundaries violate the same principle.

Republican state Rep. Ryan Spain of Peoria said that by diluting and compacting Republican votes, any coattails from a strong statewide GOP candidate would only bolster Democratic legislative success, instead of helping other party candidates.

“The outcomes seen in 2022 and 2024 in the Illinois House are statistically impossible to create without violation of the free and equal elections clause,” Spain said.

The federal Constitution does not contain a “free and fair election” clause, but the constitutions of several states do. The Illinois Supreme Court has never defined the scope of the clause, but Republicans in their lawsuit cite Pennsylvania and North Carolina state court rulings that overturned heavily gerrymandered redistricting plans “on the basis of identical or comparable constitutional provisions.”

“This court should follow suit and declare the Enacted Plan is invalid; enjoin the Illinois State Board of Elections from enforcing it, and appoint a special master to draft a redistricting plan that complies with the Illinois Constitution,” the House GOP argues.

In the federal court challenge and in legislation stating the basis for the map lines, Democrats acknowledged that partisan considerations of maximizing and protecting seats — issues that the federal court could not adjudicate — were a priority. The federal court, while rejecting the Republican challenge, acknowledged “the voluminous evidence submitted by the parties overwhelmingly establishes that the Illinois mapmakers were motivated principally by partisan political considerations.”

The every-decade process of redrawing the state’s political boundaries was complicated by the pandemic and delays in the release of the 2020 U.S. census.

Democrats sought to avoid a constitutional deadline that would have given Republicans an opportunity to control the mapmaking process by approving an initial set of maps that were based on federal census estimates. That initial plan was found unconstitutional by the federal court, but Democrats followed up with new maps based on actual census data and the federal court upheld the new boundaries that are currently in effect.