On Monday, Democrats on the Senate Judiciary Committee urged U.S. Supreme Court Chief Justice John Roberts to initiate an investigation into Justice Clarence Thomas and his wife’s undisclosed acceptance of luxury trips paid for by a Republican megadonor.

The committee plans to hold a hearing soon to address the need for restoring confidence in the Supreme Court’s ethical standards, the Associated Press reported.

If the issue is not addressed by the Supreme Court, the committee will consider voting on legislation, which would require the support of the Republican-led House to become law.

The 11 Democratic senators wrote to Roberts, stating that he does not need to wait for Congress to act and can initiate an investigation to prevent such conduct from occurring again.

The nonprofit investigative journalism organization ProPublica reported last Thursday that Thomas, who has served as a justice for more than 31 years, has accepted luxury trips from Republican donor Harlan Crow almost every year for more than two decades.

Written by staff