Chief Justice Roberts declines invitation to testify about Supreme Court ethics

Chief Justice John Roberts on Tuesday declined an invitation to testify before the Senate Judiciary Committee at a hearing about Supreme Court ethics.

Sen. Dick Durbin, chairman of the influential panel, sent a letter to Roberts last week inviting him or "another Justice whom you designate" to appear before the committee on May 2 for a hearing "regarding the ethical rules that govern the Justices of the Supreme Court and potential reforms to those rules."

Roberts replied on Tuesday that testimony by the chief justice is "exceedingly rare," noting it's only happened twice: once in 1921 and again in 1935.

He also attached a five-page statement on court ethics and practices signed by all nine justices, which Roberts said they all adhere to despite there being no independent enforcement of such rules.

The invitation for Roberts to appear before the committee came after ProPublica reporting revealed close ties between Justice Clarence Thomas and wealthy GOP donor Harlan Crow, including real estate Thomas and his family sold to Crow and extensive travel by Thomas that Crow facilitated or paid for. Those connections were not revealed on Thomas' disclosure reports.

In his letter, Durbin, D-Ill., noted that the last time the Judiciary Committee heard from sitting justices on ethics was in 2011.

"Since then, there has been a steady stream of revelations regarding Justices falling short of the ethical standards expected of other federal judges and, indeed, of public servants generally. These problems were already apparent back in 2011, and the Court's decade-long failure to address them has contributed to a crisis of public confidence. The status quo is no longer tenable," Durbin wrote.

Durbin said last week the hearing would still take place even in Roberts' absence and that there hadn't been discussion of subpoenaing Roberts.

California Sen. Dianne Feinstein's continued absence as she recovers from shingles means the panel is deadlocked between Democrats and Republicans, rather than Democrats' normal one-seat majority, and only a majority of members could vote to approve a subpoena for Roberts' testimony. It's unclear if any Republicans would back such a move.

Democrats have been up in arms following the ProPublica reports.

"This is beyond party or partisanship," Rep. Alexandria Ocasio-Cortez tweeted earlier this month. "This degree of corruption is shocking -- almost cartoonish. Thomas must be impeached."

Republicans, meanwhile, have largely fallen in line behind Thomas.

"I have total confidence in the chief justice of the United States to deal with these court internal issues," Senate Republican Leader Mitch McConnell said this week, suggesting any ethics reforms should be left to the Supreme Court to determine.

Crow has repeatedly maintained his relationship with Thomas included no wrongdoing and that he never tried to influence Thomas' work on the court.

"We have never asked about a pending or lower court case, and Justice Thomas has never discussed one, and we have never sought to influence Justice Thomas on any legal or political issue. More generally, I am unaware of any of our friends ever lobbying or seeking to influence Justice Thomas on any case, and I would never invite anyone who I believe had any intention of doing that," Crow said in a statement after the first ProPublica report was published.

In a statement, Thomas said, "Harlan and Kathy Crow are among our dearest friends, and we have been friends for over twenty-five years. As friends do, we have joined them on a number of family trips during the more than quarter century we have known them. Early in my tenure at the Court, I sought guidance from my colleagues and others in the judiciary, and was advised that this sort of personal hospitality from close personal friends, who did not have business before the Court, was not reportable. I have endeavored to follow that counsel throughout my tenure, and have always sought to comply with the disclosure guidelines. These guidelines are now being changed, as the committee of the Judicial Conference responsible for financial disclosure for the entire federal judiciary just this past month announced new guidance. And, it is, of course, my intent to follow this guidance in the future."

ABC News' Devin Dwyer contributed to this report.