Leftists expressed outrage last week after ProPublica reported that Supreme Court Justice Clarence Thomas has accepted gifts in the form of expensive trips from wealthy Republican donor Harlan Crow.

In response to the allegation, a collection of Capitol Hill Democrats have all but demanded that Chief Justice John Roberts open an investigation. 

Democrats say Roberts must "safeguard public faith in the judiciary"

According to Fox News, the group is being led by Rhode Island Sen. Sheldon Whitehouse and Georgia Rep. Hank Johnson.

They and their colleagues sent a letter on Friday in which they called on Roberts to investigate "allegations of unethical, and potentially unlawful, conduct."

"We believe that it is your duty as Chief Justice 'to safeguard public faith in the judiciary,' and that fulfilling that duty requires swift, thorough, independent and transparent investigation into these allegations," the lawmakers insisted.

Fox News noted that Thomas has issued a rare statement in which he denied wrongdoing and insisted that he has always complied with the Supreme Court's reporting requirements.

Thomas says previous trips were not reportable under Supreme Court rules

"Harlan and Kathy Crow are among our dearest friends, and we have been friends for over twenty-five years," Fox News quoted Thomas' statement as saying.

"As friends do, we have joined them on a number of family trips during the more than quarter century we have known them," it continued.

"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," the Supreme Court justice added.

"I have endeavored to follow that counsel throughout my tenure, and have always sought to comply with the disclosure guidelines,"  he said.

Harlan insists he has "never sought to influence Justice Thomas"

"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," Thomas explained before pledging that it is his "intent to follow this guidance in the future."

Meanwhile, Fox News reported that Crow also released a statement to ProPublica in which he too disputed that any impropriety had taken place.

"The hospitality we have extended to the Thomas’s (sic) over the years is no different from the hospitality we have extended to our many other dear friends," Harlan insisted.

"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," the GOP donor contended.