As the latest polling showed a majority of Americans believe U.S. Supreme Court Justice Clarence Thomas should step down from his lifetime appointment, government watchdog Accountable.US deployed several trucks to Capitol Hill Saturday to display mobile billboards plastered with Thomas' and other right-wing justices' images and recent headlines regarding allegations of ethics violations.

An image of Thomas was shown alongside a headline reading, "America's Supreme Court Faces a Legitimacy Crisis," while Chief Justice John Roberts was displayed with the message: "Justice Roberts: Clean Up Your Court."

"It's never a bad day to remind SCOTUS Chief Justice Roberts of the rampant corruption and scandals that plague his Court," said the group, which also sent a mobile billboard to Roberts' country club.

The campaign took place a day after progressive think tank Data for Progress published survey results showing that 53% of respondents believed Thomas should resign following revelations that he's financially benefited for years from trips and other gifts given to him by Republican megadonor Harlan Crow, as well as from a property sale to Crow.

Seventy percent of people told Data for Progress the previously undisclosed property sale was unethical and 64% said the same about his vacations and gifts.

Thomas was the first right-wing judge to come under scrutiny for his failure to disclose his financial ties—a violation of federal law, according to legal experts.

Earlier this week Politico reported that Justice Neil Gorsuch sold a property to a law firm CEO days after being confirmed to the court—but didn't disclose the name of the buyer on federal forms. The CEO's firm has been involved in nearly two dozen cases that have gone before the court since Gorsuch was appointed.

On Friday, whistleblower documents sparked renewed interest in the earnings of Roberts' wife, Jane Sullivan Roberts, who made $10.3 million in commissions from a legal recruiting firm she worked at between 2007 and 2014, placing lawyers at firms—including at least one that argued a case before the high court. Roberts did not specify that his wife had earned that money in commissions from law firms in his federal disclosure forms.

"In addition to Clarence Thomas and his issues, we have Justice Gorsuch and his issues, and we've got the chief justice's wife and her issues," said U.S. Rep. Bonnie Watson Coleman (D-NJ) on Saturday. "It tells you that unaccountability leads to corruption. The American people need and deserve a fair and ethical Supreme Court."

Watson Coleman also called for an expansion of the court, which has been endorsed by numerous progressives in Congress and legal advocacy groups.

The Supreme Court is not bound by a code of ethics, as other federal courts are. Forty-eight percent of respondents told Data for Progress that they supported binding rules, including 67 percent of Democrats.

"These revelations have renewed pressure on the court to follow an explicit code of conduct," said the think tank. "While all nine justices have so far been resistant to the idea, voters clearly support ensuring that the Supreme Court justices are held to an ethical standard, and also support consequences for justices who fail to do so."