CHICAGO (AP) — Michael Madigan, the Chicago Democrat who for decades led the Illinois House of Representatives before recently resigning the Legislature amid an ongoing federal probe that implicated him in a long-running bribery scheme, quit Monday as state party chairman.

Madigan, 78, did not give a reason for resigning as party chairman, a post he's held since 1998.

“It’s no secret that I have been the target of vicious attacks by people who sought to diminish my many achievements lifting up the working people of Illinois,” Madigan said. “The fact is my motivation for holding elected office has never wavered. I have been resolute in my dedication to public service and integrity, always acting in the interest of the people of Illinois.”

Cook County Clerk Karen Yarbrough will be appointed as interim leader of state Democrats until a permanent replacement is named.

Jockeying to be Madigan’s permanent successor has begun, with Congresswoman Robin Kelly announcing plans to seek the party chairmanship.

“With democracy under siege, it’s more important than ever that we have leaders of our party that can appeal to the broad sector of our electorate that represent all 102 counties of our state,” said the 2nd Congressional District representative. ”As Chair, I will bring a fresh approach that includes my collaborative and inclusive work ethic.”

In July, Madigan, the longest-serving legislative leader in U.S. history, was implicated in a long-running bribery scheme involving the state’s largest electric utility, Commonwealth Edison. Court filings didn’t name Madigan but made it clear he was the person in documents referred to as “Public Official A.” ComEd admitted it secured jobs, often requiring little or no work, and contracts for his associates from 2011 to 2019 for favorable treatment in regulations. ComEd agreed in August to pay $200 million.

News of the investigation caused a loss of support among members of the Democratic delegation in the House, costing him the speakership. He resigned from the Legislature on Thursday.

In a statement, Yarbrough said Illinois is a reliably blue state based in large part because of the leadership of Madigan.

“Democrats across Illinois owe Chairman Madigan a huge debt of gratitude for the support, resources and time he’s dedicated to candidates and races at every level,” Yarbrough said. ``While our party enters a transition and looks to the future, I hope we don’t lose sight of the extraordinary contributions he has made.”

Yarbrough has been Cook County clerk for two years, overseeing elections, birth and death certificates and other public records in the county. She’s also been a state representative and the county’s recorder of deeds.

Copyright 2021 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.