Conservative activist Leonard Leo has been subpoenaed by the Senate Judiciary Committee related to an investigation into Supreme Court ethics in what he calls a "politically motivated" move that he will not abide by. 

"Today, I received an unlawful and politically motivated subpoena from Senate Judiciary Committee Chairman Dick Durbin," Leo said in a statement on Thursday. 

"I am not capitulating to his lawless support of Senator Sheldon Whitehouse and the left's dark money effort to silence and cancel political opposition."

Leo was subpoenaed by the committee in what is the latest back and forth between Senate Democrats and Leo as the Senate has continued summoning information regarding trips and events that Supreme Court justices have taken and participated in over the years. 

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Leo Durbin

Senate Judiciary Committee Chairman Dick Durbin, D-Ill., left, and Leonard Leo. (Getty Images)

For decades, Leo has been a part of the Federalist Society, which has long been criticized by liberal activists for its involvement in helping advise and lobby former President Donald Trump through the nominations of Supreme Court Justices Neil Gorsuch, Brett Kavanaugh and Amy Coney Barrett.

The senators have previously asked for an itemized list of gifts and payments from Leo or groups he is associated with dating back decades and related to any Supreme Court justice he has associated with amid public outcry from Democrats accusing Supreme Court Justice Clarence Thomas of ethics violations, which have been dismissed by many as politically motivated. 

In a Thursday letter to Durbin, the chairman of the Senate Judiciary, Leo’s lawyer David Rivkin Jr., reiterated Leo is "not complying" with the "unlawful and politically motivated subpoena."

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Dick Durbin

Sen. Richard Durbin, D-Ill., attends a Senate Judiciary Committee hearing to examine Texas' abortion law on Capitol Hill in Washington, D.C., on Sept. 29, 2021. (Tom Williams-Pool/Getty Images)

The senators' demands stem from ProPublica's reporting on the travel habits of Justices Thomas and Alito. Specifically, ProPublica reported on an Alaskan fishing trip that Justice Alito took with hedge fund billionaire Paul Singer, who would later have business matters before the high court.

Conservatives have widely criticized the effort by pointing out that many of the "experts" cited in the various reports have undisclosed ties to Democratic causes.

The committee has also previously authorized a potential subpoena for GOP donor Harlan Crow related to gifts he gave Thomas and called the two subpoenas "key pieces of our legislative effort to establish an effective code of conduct" for the Supreme Court.

Conservatives have called out ProPublica for being primarily funded by organizations and donors who support liberal causes, including court-packing and removing conservative justices from the court.

Alito has defended himself against ProPublica's reporting, and Leo has released a statement dismissing the idea that the fishing trip was somehow kept from the public.

"By selectively targeting Mr. Leo for investigation on a politically charged basis, while ignoring other potential sources of information on the asserted topic of interest who are similarly situated to Mr. Leo but have different political views that are more consistent with those of the Committee majority, your inquiry appears to be political retaliation against a private citizen in violation of the First Amendment," Rivkin previously wrote to the committee.

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Supreme Court Justice Clarence Thomas

Associate Supreme Court Justice Clarence Thomas speaks at the Heritage Foundation in Washington, D.C., on Oct. 21, 2021. (Drew Angerer/Getty Images)

Leo and his legal team have also pointed out that trips taken by former Supreme Court Justice Stephen Breyer and money received by late Supreme Court Justice Ruth Bader Ginsburg have not resulted in inquiries from the committee.

"Since July 2023, Leonard Leo has responded to the legitimate oversight requests of the Senate Judiciary Committee with a blanket refusal to cooperate," Durbin told Fox News Digital in a statement. 

"His outright defiance left the Committee with no other choice but to move forward with the compulsory process. For that reason, I have issued a subpoena to Mr. Leo."

The statement continued: "Mr. Leo has played a central role in the ethics crisis plaguing the Supreme Court and, unlike the other recipients of information requests in this matter, he has done nothing but stonewall the Committee. This subpoena is a direct result of Mr. Leo’s own actions and choices."

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supreme court exterior

The U.S. Supreme Court. (AP Photo/Mariam Zuhaib, File)

An aide for Durbin told Fox News Digital that while the senator "certainly expects the subject to acknowledge the gravity of a congressional subpoena," there are "options available to the Senate to enforce a subpoena in the event of noncompliance."

Fox News Digital reached out to the White House for comment but did not immediately receive a response.

In November, the Supreme Court adopted a modified ethics code in response to pressure from Durbin's committee and others.