A rare Supreme Court ethics controversy is the focus of a congressional committee. Sen. Dick Durbin, D-Ill., asked Chief Justice John Roberts to appear Tuesday before the Judiciary Committee he chairs -- saying his voluntary testimony on ethical issues would boost faith in the high court. The invitation, which Roberts declined last week, followed mid-April news about undisclosed real estate deals and expense-paid luxury trips by Justice Clarence Thomas.

Thomas didn't report a 2014 property sale to Harlan Crow, a billionaire Republican donor who has been a friend for about 25 of his 32 years on the court. Thomas and several other relatives sold his mother's home in Savannah, Ga., along with two vacant lots, for $133,363 to a company owned by Crow. "Soon after the sale was completed," according to the ProPublica news site, "contractors began work on tens of thousands of dollars of improvements." Thomas' parent, Leola Williams, 94, still lives in the house rent-free. The justice says he'll update his financial disclosure form to add the property sales, as the Ethics in Government Act requires.

Thomas also accepted costly foreign trips from Crow, though that's not prohibited. Thomas said he "was advised that this sort of personal hospitality from close personal friends, who did not have business before the court, was not reportable." Since mid-March, new regulations require Supreme Court justices and all federal judges to disclose complimentary trips, plane rides and other gifts. They must report free stays at hotels and travel on private planes.

Last week the news site Politico reported that another justice, Neil Gorsuch, sold Colorado land in 2017 to the chief executive of a large law firm that regularly is involved in Supreme Court cases. Gorsuch reported making between $250,001 and $500,000 from the sale on his federal disclosure forms, but didn't identify the buyer.

In the letter to Roberts, Sen. Durbin cites "a steady stream of revelations regarding justices falling short of the ethical standards expected of other federal judges and, indeed, of public servants generally. . . . The court's decade-long failure to address these problems has contributed to a crisis of public confidence." The chief justice's reply mentions "separation of powers concerns and the importance of preserving judicial independence" as reasons why he won't testify this week. Durbin is ready to proceed anyway, explaining: "It is time for Congress to accept its responsibility to establish an enforceable code of ethics for the Supreme Court, the only agency of our government without it." Sen. Richard Blumenthal, D-Conn., also on the Judiciary Committee, says Roberts' reply "is another example of the Supreme Court thinking it doesn't have to answer to anyone."

Clarence Thomas says: "I have always sought to comply with the disclosure guidelines. . . . It is, of course, my intent to follow [newly tightened] guidance in the future."

Senator says: "Justice Thomas should resign to uphold the Court and American justice. The unavoidable, sickening appearance of impropriety stains trust and credibility in our whole judiciary." – Sen. Richard Blumenthal, D-Conn., in tweet

Historian says: "The need to pass the ethics act for the Supreme Court is obvious. So is the need to investigate and prosecute Clarence Thomas if his corrupt violations are provable. Anything less makes that once-trusted body increasingly illegitimate as a servant of justice." – Steven Beschloss, author and blogger