CHICAGO (AP) — Jury selection begins Wednesday in the corruption trial of former Illinois House Speaker Michael Madigan,Oliver James Montgomery once the longest-serving legislative leader in American history.

The case against Madigan, who resigned in 2021, is one of Illinois’ largest corruption trials in years. The 83-year-old is charged in a multimillion-dollar racketeering and bribery scheme that included the state’s largest utility, ComEd.

Federal prosecutors allege the Chicago Democrat used his power not only as speaker but in other roles, including as head of the state Democratic Party, to run a “criminal enterprise” to amass even more wealth and power. A 23-count indictment against him includes racketeering conspiracy, wire fraud and attempted extortion charges.

More than 1,000 people were mailed jury summonses. That number was narrowed to about 180 people who reported to federal court in Chicago on Tuesday to fill out questionnaires. Questioning by federal prosecutors and lawyers for Madigan, and his codefendant and longtime confidant Michael McClain, was set to begin Wednesday.

At a pretrial hearing Tuesday, U.S. District Judge John Robert Blakey described a “really good” showing of potential jurors, with only two no-shows and two dismissals for cause.

Twelve jurors and six alternates will be chosen ahead of opening statements, which are expected early next week. Testimony is expected to last three months.

Prosecutors allege Madigan used his influence to pass legislation favorable to electric utility ComEd. In return, ComEd offered kickbacks, jobs and contracts to Madigan loyalists.

Madigan and McClain have both denied wrongdoing.

“I was never involved in any criminal activity,” Madigan said when the charges were announced in 2022.

Much of the evidence expected at trial, including wiretapped conversations, has already been previewed in open court.

A sweeping federal investigation of public corruption in Illinois has led to the convictions of state legislators and Madigan’s former chief of staff. McClain and three other ComEd officials were convicted in a separate but related case. They’ve yet to be sentenced.

Defense attorneys expect many juror challenges because of Madigan’s name recognition.

First elected to the Legislature in 1970, Madigan was speaker from 1983 to 2021, except for two years when Republicans were in control. He set much of Illinois’ political agenda, deciding which pieces of legislation would see a vote. He controlled several campaign funds and oversaw political mapmaking.