Facing 20 felony counts of abusing power while in office, state Sen. Chuck Chvala, D-Madison, announced Thursday he would resign from his post as Senate Majority Leader.

In a criminal complaint filed earlier the same day by Milwaukee County District Attorney E. Michael McCann, an investigator into the Senate Democratic caucus, Chvala was charged with three counts of extortion, seven counts of misconduct in public office, one count of making unlawful political contributions, four counts of making campaign contributions exceeding lawful limits and five counts of filing a false report with the state elections board.

Chvala, who maintains his innocence, made a failed attempt to stall the proceedings Wednesday, claiming McCann had a conflict of interest in the case and should be removed.

Chvala asserts the decision to proceed with the charges was nothing more than an attempt by the D.A. to influence the approaching Nov. 5 elections.

“There is no question that this action today, just weeks before the fall elections, in an investigation that has dragged on for almost a year and a half, is designed to have a political impact,” Chvala said in a statement. “I will fight these allegations because they are not true. But I have decided that, in the interest of the Senate, I will resign as Majority Leader as soon as a new leader is selected.”

A new Senate Majority Leader could be appointed as soon as this weekend.

In charging Chvala Thursday, prosecutors claimed he demanded campaign contributions from lobbying groups while threatening to block legislation without the donations, and used state-employed aides to work on Democratic candidates’ campaigns on state time.

The charges are the latest development in a 16-month investigation into illegal campaign practices of Wisconsin lawmakers and employees.

If convicted, Chvala could face up to 90 years in prison and $200,000 in fines.

Chvala’s resignation announcement came after several state democrats demanded Chvala step down from his leadership position.

“Legislative leaders charged with criminal wrongdoing cannot effectively perform their duties,” Sen. Kin Plache, D-Racine, said. “As public servants, they must surrender their leadership posts so the Legislature can function without a cloud of corruption hanging over its head.”

Libertarian gubernatorial candidate Ed Thompson praised the charges against Chvala Wednesday but called for additional charges against other lawmakers suspected of illegal activity.

“Charging Senator Chvala is not enough. We need charges against the Senate and Assembly members who ran the Democratic Assembly caucus and the Republican Assembly and Senate caucuses,” Thompson said.

According to the criminal complaint, additional charges against other individuals are likely. So far, Sen. Brian Burke, D-Milwaukee, is the only other lawmaker charged in the investigation.

Chvala has been the leader of Senate Democrats since 1996. He holds one of the most powerful positions in state government because he has the power to determine which bills reach the Senate floor.