The Illinois Supreme Court ruled against the proposed Independent Map Amendment on Thursday, preventing the redistricting referendum from appearing on the November ballot.
The 4-3 ruling affirms the lower court's decision in the case. In July, a Cook County judge sided with opponents of the Independent Map Amendment, who argued that the effort is unconstitutional and places new roles on the Illinois Supreme Court and auditor general.
The Independent Maps group, which gathered over 563,000 signatures from Illinois voters to get the proposed constitutional amendment on the ballot, expressed disappointment over the Supreme Court's ruling and said it is considering whether to seek a rehearing.
"Drafters of the Illinois Constitution would not recognize the interpretation made by the Supreme Court majority," Independent Maps Chair Dennis FitzSimons said in a statement. "According to the majority, voters cannot propose sensible changes to the legislative article that would make a meaningful difference in the way legislative district boundaries are drawn."
Illinois Gov. Bruce Rauner backed the Independent Map Amendment.
"Today's court decision to deny Illinoisans the right to vote on a redistricting referendum does nothing to stem the outflow or change people's views of how the system is rigged and corrupt," the governor said in a statement. "When the General Assembly reconvenes this fall, they should put political reform - term limits and independent redistricting - at the top of the legislative agenda so that incumbents aren't locked into power and democracy is restored through competitive general elections."
Currently, the Illinois General Assembly drafts the state's legislative boundaries every 10 years following the release of the decennial Census. Under the proposed Independent Map Amendment, a non-partisan, 11-member independent commission would draw the state's legislative district maps.
The lawsuit against the Independent Map Amendment was filed by the People's Map group, which worked with an elections attorney who has connections to House Speaker Michael Madigan.
The attorney successfully blocked a similar map amendment attempt in 2014.
The People's Map opposed the plan, in part, over concerns that it could harm minority participation and representation.
"Any attempt to weaken the rights of minority voters is an attack on democracy itself, making today's ruling a victory for a fair and truly accountable electoral process," reads a statement from the People's Map Chairman John Hooker.