Three leading Senate Democrats said Tuesday that all options are on the table after billionaire Harlan Crow refused again to answer their questions about the gifts and other financial support hes given to Supreme Court Justice Clarence Thomas.

Senate Judiciary Committee chair Dick Durbin (D-Ill.), along with courts subcommittee chair Sheldon Whitehouse (D-R.I.), and Senate Finance Committee chair Ron Wyden (D-Ore.) sought to question Crow after ProPublica revealed that Thomas failed to disclose Crows lavish gifts to him in the form of private jet travel, luxury vacations and private club admissions. Thomas also failed to disclose that he sold his ancestral home to Crow in 2014 and that Crow paid the private school tuition of Thomas grandnephew, whom Thomas treated as an adopted son.

The Judiciary Committee is investigating the courts failure to abide by a binding ethics code, as all other federal courts do, while it considers legislation requiring the Supreme Court to follow one. The Finance Committee is looking into whether Crow paid gift taxes for his largesse to Thomas.

Crow rebuffed both committees in May by claiming the Supreme Courts separation of powers protection for himself as a private citizen. His lawyer argued that the committees did not have a legitimate legislative purpose in their investigations because Congress cannot pass legislation to impose ethics laws on the Supreme Court. He reiterated his refusal to provide answers in a second round of letters to both committees.

Lets be clear: Harlan Crow doesnt call the shots here, Durbin and Whitehouse said in a statement. He is not a branch nor even a member of government and cannot claim the protections and privileges of one. The Senate Judiciary Committee has clearly established oversight and legislative authority to assess and address the ethical crisis facing the Court. All options are on the table moving forward.

Those options could include a subpoena, according to Wyden.