Justice Clarence Thomas
The subpoena relates to Justice Clarence Thomas' (pictured) lavish trips allegedly paid for by GOP megadonor Harlan Crow. Reuters

Senate Democrats issued a subpoena to a conservative legal advocate Thursday as part of their investigation into a string of ethics controversies involving allegations of extravagant travel and gifts provided to justices.

Senate Judiciary Committee Chair Dick Durbin announced that the committee has officially issued the subpoena to Leonard Leo for gaining insights into whether certain individuals and organizations have utilized undisclosed gifts to secure access to the justices.

The subpoena comes months after the committee's partisan vote to subpoena Leo and GOP megadonor Harlan Crow following reports alleging that Supreme Court Justices Clarence Thomas and Samuel A. Alito accepted undisclosed luxury gifts and travel trips.

The reasons for the delay between the November vote and the issuance of the subpoena remain unclear.

Durbin said in a statement to CNN that Leo had been at the forefront of the ethics issues surrounding the Supreme Court, and unlike others who had received information requests in this matter, he had consistently refused to cooperate with the committee.

"This subpoena is a direct result of Mr. Leo's own actions and choices," Durbin said.

Leo, co-chairman of the influential Federalist Society board, played a crucial role in vetting potential nominees for the nation's highest court during the tenure of former President Trump. He acknowledged Thursday that he had been served with a subpoena and vowed not to comply.

Describing the subpoena as "unlawful" and "politically motivated," Leo told CNN that he would not yield to what he characterized as the "left's dark money effort to silence and cancel political opposition."

Leo's attorney, David Rivkin, sent a letter to Durbin stating that his client is refusing to comply with the "unlawful and politically motivated subpoena." Should Leo refuse to comply, Democrats may need to initiate a vote and secure 60 votes in the divided chamber to enforce the subpoena.

The committee's vote last autumn descended into partisan discord, with Republicans accusing Democrats of political maneuvering and subsequently leaving the session.

A ProPublica report in June 2023 said that Crow funded extravagant trips for Justice Thomas, which were not initially disclosed on the justice's financial reports. According to another ProPublica report, Leo organized a fishing expedition in 2008 that Justice Alito attended, also unreported on his financial disclosures.