WASHINGTON – The Republicans for the Rule of Law debuted an impeachment-based digital billboard in Times Square asking “What is (President Donald) Trump hiding?”

The billboard comes as the entire House is expected to hold a vote on the two articles of impeachment towards the president —abuse of power and obstruction of Congress charges.

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The ad takes direct aim at the latter charge, featuring current and former Trump administration officials who were involved in the Ukraine scandal and yet did not comply with congressional subpoenas to testify.

Sporting duct tape over their mouths on the billboard include Secretary of State Mike Pompeo, former national security adviser John Bolton, acting chief of staff Mick Mulvaney and Rudy Giuliani, Trump’s personal attorney.

The president is displayed as hushing these individuals on the billboard.

The Trump administration has directed aides and agencies to defy subpoenas for documents and testimony, although some officials still testified. The defiance is what led to the accusation of obstruction of Congress. Judiciary Chairman Jerry Nadler, D-N.Y., said Trump's refusal to cooperate with any congressional subpoena was worse than any president in history, including Nixon.

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Republicans for the Rule of Law Executive Director Sarah Longwell said in a statement that "President Trump is refusing to comply with a congressional investigation, and is directing his unelected subordinates to obstruct the people’s House."

"Republicans should remember their forebears as well as the precedent they are setting, and uphold their duty to the Constitution," she continued.

Beyond Times Square, Republicans for the Rule of Law additionally displayed the ad in Congressional districts of House Republicans who have shown signs of independence from Trump, and whom the group thinks could stand up and call on the administration to let the witnesses testify, Republicans for the Rule of Law told USA TODAY.

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These Congressional districts include those of Reps. Mo Brooks (R-Ala.), Brian Fitzpatrick (R-Pa.), John Katko (R-N.Y.), Adam Kinzinger (R-Ill.), Cathy McMorris Rodgers (R-Wash.), Michael McCaul (R-Texas), Paul Mitchell (R-Mich.). Martha Roby (R-Ala.), Mac Thornberry (R-Texas), Fred Upton (R-MI) and Greg Walden (R-Ore.)

Republicans for the Rule of Law spokesman Chris Truax asked in a statement, "If President Trump really could prove he is innocent of the impeachment charges against him, he would have made some effort to do so by now. If the President really does think the facts will exonerate him, why won't he let those facts come out?"