He’s been called “the Velvet Hammer” for his quiet, forceful style of leadership, but on Tuesday, Mike Madigan was the one taking a pounding.

All three leading Democratic gubernatorial candidates joined a growing group of Democrats calling for an independent investigation into what one state legislator dubbed the “endless cycle of lather, rinse, repeat” of harassment allegations and “culture that appears to pervade the organizations led by Speaker Madigan.”

And one of them — Rep. Scott Drury of Highwood — also called on Mike Madigan to step down as House speaker. Drury is part of a small but growing chorus of Democrats demanding Madigan step down as speaker, state Democratic Party leader or both.

“Something’s rotten in the 13th Ward,” Sharon Fairley wrote on her Facebook page, calling on Madigan to quit as speaker and party chairman. “Obviously, a culture exists that sanctions this kind of behavior and a code of silence that protects the abusers.”

Fairley and Drury are both running in the Democratic primary for attorney general.

Drury is a frequent Madigan critic, but even more telling was the call by J.B. Pritzker for an independent probe. The billionaire gubernatorial candidate has come under fire for being slow to take Madigan to task.

“It’s clear that not enough was done and there needs to be a completely independent investigation to get to the bottom of what took place and hold the right people accountable,” Pritzker said in a statement. “I agree with Rep. Kelly Cassidy and believe the people investigating Speaker Madigan’s operation should have no political or other ties to the Speaker.”

Pritzker was referring to Cassidy’s interpretation of the way Speaker Mike Madigan has dealt with the latest round of harassment claims — as the Chicago state representative offered up some of the strongest criticism thus far from within the powerful Southwest Side Democrat’s own caucus.

“The slow and steady drip of accusations and dismissals has turned into an endless cycle of lather, rinse, repeat, highlighting the culture of harassment in the legislature and political campaigns,” Cassidy said in a statement. “I am calling for an independent investigation into this culture that appears to pervade the organizations led by Speaker Madigan.”

It prompted a response from the speaker.

“I spoke with Kelly Cassidy today. I told her I will cooperate fully and I will ask independent counsel Kelly Smith-Haley to assist,” Madigan said in a statement. Smith-Haley is the attorney the speaker chose last week to “provide independent review of allegations, conduct investigations and provide recommendations.”

Cassidy said she spoke with Madigan on Tuesday: “He never mentioned the firm or this attorney, but he indicated he was willing to cooperate.”

The fact that Madigan has chosen the attorney deemed “independent” is raising some eyebrows. And with Madigan’s daughter, Lisa Madigan, serving as Illinois attorney general, a usually independent third party isn’t an option. The process is highlighting the many ties the country’s longest-serving state House speaker has to everyone from lobbyists to lawyers to legislators.

State Sen. Melinda Bush, D-Grayslake, also called for an independent investigation.

“I still do have concerns,” Bush said in response to the speaker’s assertion that he’ll “cooperate fully” with Cassidy’s request for an independent investigation. “The problem is, who pays for an independent counsel?”

In addition to an independent statewide investigation, Drury, a Democratic maverick who toyed with challenging Madigan for speaker, is also asking for the speaker to go under oath to talk about how he’s handled sexual harassment allegations and to step down as speaker — something Madigan has already vowed not to do.

And the controversy even reached a congressional race. Marie Newman, a Democrat challenging U.S. Rep. Dan Lipinski in the 3rd Congressional District, in a statement said Madigan should resign as chairman of the state’s Democratic party, while describing the latest allegations as “the product of a culture of sexism that pervades our political environment in Illinois.”

“Anything less would put the Democrats’ political prospects at risk in November — and more importantly, would send a signal to all victims that their voices don’t matter, and that the status quo will never be disrupted,” Newman said of her calls for Madigan to resign.

Lipinski, however, said Madigan has taken responsibility and admitted he must do better: “He appears to have taken a number of steps to ensure that women are better protected in the statehouse and on the campaign trail and that action will be taken against perpetrators,” Lipinski said. “I have confidence that Mike Madigan in his roles as Democratic Party Chairman and Speaker of the House will be a powerful force for change for women.”

In the governor’s race, Pritzker joins primary rivals Daniel Biss and Chris Kennedy in seeking an independent investigation. Unlike Pritzker, Biss and Kennedy have also called for Madigan to step down as party chairman,

Kennedy has called on Madigan to temporarily step down, saying Madigan “chose to protect his machine political allies instead of the women who were abused by them” and “he no longer can lead our party.”

The fallout for Madigan comes a day after the speaker announced the firing of another aide for “inappropriate behavior” toward a candidate and staff during the 2016 election.

Shaw Decremer became the second Madigan operative to be dismissed this month. Decremer, a lobbyist, was removed last week from four Democratic Illinois House campaigns, according to Democratic sources. His exit came seven days after the firing of Madigan’s longtime aide Kevin Quinn, after a woman came forward to detail unwanted advances from Quinn, the brother of Ald. Marty Quinn (13th).

Cassidy, Bush, Drury, Kennedy, Biss and Pritzker are all calling for a more independent process to investigate such allegations.

That’s at odds with Madigan’s efforts last week to address the problem by creating a process in which victims of harassment could reach out to attorneys Madigan provided or be referred to outside resources. In a letter to Democratic caucus members, state and political staffers, Madigan last week also wrote that it’s time to “rethink the culture of politics.”

“We haven’t done enough. I take responsibility for that,” Madigan said. “I would never condone, sweep under the rug or refuse to take any step to ensure we did not eradicate any behavior of this kind.

But Cassidy on Tuesday highlighted what she called a cycle that needs change.

“We must get to the bottom of this with confidence in the independence of the investigator. We need to force the very real culture change required to truly show that #times up,” Cassidy said.

Cassidy said the investigator shouldn’t be an elected official or firms with ties to the speaker. In a letter sent to Democratic House members on Friday, the speaker listed names and numbers of attorneys for political and state staffers to reach out to for “confidential guidance” or to “direct staff to an outside resource.”

Cassidy said she has reached out to Women Employed and the National Women’s Law Center for recommendations on how to create a more independent process.

And Cassidy last week — in response to allegations that someone within Madigan’s political organization tried to find “dirt” on Alaina Hampton, the woman who accused Kevin Quinn of misconduct — said leaders “own” the culture they create.

“We own the culture of the organization we create and if this person believes this was the path to his good graces, then that has to be addressed,” Cassidy said.

Madigan spokesman Steve Brown denied that the man trying to smear Hampton acted on behalf of Madigan or his organization.

Reached by phone on Tuesday, Majority Leader Barbara Flynn Currie, Madigan’s top female lieutenant, said she had “nothing to add,” about the latest calls for a special investigation.

Last week, Flynn Currie said the speaker acted “appropriately and in a timely manner” regarding Hampton’s allegations.