Senate Democrats said Monday they plan to subpoena Republican megadonor Harlan Crow and conservative activist Leonard Leo for more information about their roles in organizing and paying for luxury travel for Supreme Court justices.

The announcement by Democrats on the Senate Judiciary Committee comes as the court is being pressed to adopt an ethics code, a move that has been publicly endorsed by three of the nine justices.

The committee could act as soon as next week to authorize Sen. Dick Durbin, D-Ill., the panel’s chairman, to issue subpoenas to Crow, Leo and another wealthy donor, Robin Arkley II.

Crow has been identified as a benefactor of Justice Clarence Thomas for more than two decades, paying for nearly annual vacations, purchasing from Thomas and others the Georgia home in which the justice’s mother still lives and helping pay for the private schooling for a relative.