MADISON, Wis. (AP) — Wisconsin’s Republican Assembly speaker revealed the names of the three former conservative state Supreme Court justices he asked to investigate possible impeachment of a sitting liberal justice for the first time in a court filing made public Wednesday.

Assembly Speaker Robin Vos floated impeaching liberal Justice Janet Protasiewicz if she did not recuse from a redistricting lawsuit seeking to toss GOP-drawn legislative district boundary maps. On Friday, she declined to recuse herself, and the court voted 4-3 along partisan lines to hear the redistricting challenge.

Vos asked three former justices to review the possibility of impeachment, but he refused to name them. David Prosser told The Associated Press that he was on the panel, but other justices either said they weren’t on it or did not comment.

In a court filing, Vos identified the other two as former Chief Justice Patience Roggensack and former Justice Jon Wilcox. All three of those picked by Vos are conservatives. Roggensack served 20 years on the court and her retirement this year created the vacancy that Protasiewicz filled with her election win in April.

Wilcox was on the court from 1992 to 2007 and Prosser served from 1998 to 2016.

Prosser, a former Republican Assembly speaker, sent Vos on email on Friday advising against moving forward with impeachment. That was after a state judiciary disciplinary panel rejected several complaints lodged against Protasiewicz that alleged she violated the judicial code of ethics with comments she made during the campaign.

Prosser turned that email over to the liberal watchdog group American Oversight as part of an open records request. The group is also suing, arguing that the panel created by Vos is violating the state open meetings law.

Vos, in his court filing Wednesday, said he never asked the three retired justices to prepare a report or any other written work. The recommendations of the other two former justices have not been made public. Neither Roggensack nor Wilcox returned voicemail messages Wednesday.

“Indeed, I have not provided them any formal direction,” Vos said. “Rather, I have asked each of them individually to provide me with guidance on the standards for impeachment and impeachable offenses under the Wisconsin Constitution. I did not know what feedback I would receive from each of three justices, as the advice they seek to provide me will be entirely their decision.”

Vos said that his seeking advice from the former justices was no different from any lawmaker meeting privately with someone and is not a violation of the state open meetings law.

“I have never asked them to meet with one another, to discuss any topics, or to conduct any governmental business,” Vos told the court. “I do not know whether the retired justices have or will collaborate with one another, as I have not given them a directive on how they are supposed to research the topic of impeachment.”

Vos raised the threat of impeachment in August just after Protasiewicz joined the court, flipping majority control from conservatives to liberals for the first time in 15 years. He announced creation of the panel to investigate impeachment on Sept. 13.

Vos argued that Protasiewicz had prejudged the redistricting case when during her campaign she called the maps “rigged” and “unfair.” Vos also said that her acceptance of nearly $10 million from the Wisconsin Democratic Party would unduly influence her ruling.

Protasiewicz on Friday rejected those arguments, noting that other justices have accepted campaign cash and not recused from cases. She also noted that she never promised or pledged to rule on the redistricting lawsuit in any way.

Other justices, both conservative and liberal, have spoken out in the past on issues that could come before the court, although not always during their run for office like Protasiewicz did. Current justices have also accepted campaign cash from political parties and others with an interest in court cases and haven’t recused themselves. But none of them have faced threats of impeachment.