(CNN) — Chief Justice John Roberts has declined to directly respond to a congressional request to investigate Justice Clarence Thomas' alleged ethical lapses.
Roberts instead referred the request from Senate Judiciary Chairman Dick Durbin to the Judicial Conference, which serves as the policy-making body of the federal courts.
The Illinois Democrat had penned a letter urging Roberts to investigate Thomas after a ProPublica report that found that Thomas had gone on several luxury trips at the invitation of a GOP megadonor. The trips were not disclosed on Thomas' public financial filings.
Thomas said in a statement that he had not reported the trips because the ethics guidelines in effect at the time had not required such disclosures.
Durbin has also sent a separate letter to Roberts asking him to testify in an upcoming hearing regarding Supreme Court ethics. Roberts has yet to respond to that letter .
The senator said in a statement Saturday, "It is clear that such an appearance by the Chief Justice may be the only way for the Court to set out with clarity and meaningful and credible reform."
He added that if the "Court does not address shortcomings in its ethical standards," then Congress must.
Durbin's statement included a letter from Judge Roslynn R. Mauskopf, the secretary of the Judicial Conference, that said, "I write in response to the letter of April 10, 2023, from you and other members of the Senate Judiciary Committee to the Chief Justice of the United States, which has been referred to me."
Mauskopf added that she would send the matter to the conference's Committee on Financial Disclosure.
The Judicial Conference has already received a separate but similar letter from Democratic Sen. Sheldon Whitehouse of Rhode Island.
Thomas' relationship with GOP donor Harlan Crow is not the only ethics controversy in recent year that has brought scrutiny to the high court. Critics seized on Thomas' participation in cases connected to the 2020 presidential election after CNN revealed last year that his wife, Ginni Thomas, had exchanged texts with Mark Meadows -- then-President Donald Trump's White House chief of staff -- about Trump's efforts to overturn the results.
The House Judiciary Committee, when it was controlled by Democrats last year, held a hearing on Supreme Court ethics that looked at allegations of a well-financed, secret campaign seeking to influence the high court's conservatives.
The absence of any reference to ethics, given those controversies, in Roberts' end-of-the-year report for 2022 was a surprise to some court observers.
