WASHINGTON — House Republicans used their time with former special counsel Robert Mueller to undermine his investigation into Russian interference in the 2016 election and argue that President Donald Trump is above the law.

The Justice Department’s Office of Legal Counsel has long held that the president cannot be indicted while in office. But Republicans on the House Judiciary Committee suggested during Mueller’s testimony on Wednesday that investigators should never have probed Trump’s conduct to begin with.

“Since you decided under the OLC opinion that you couldn’t prosecute a sitting president, meaning President Trump, why did we have all of this investigation of President Trump that the other side is talking about when you knew that you weren’t going to prosecute him?” asked Rep. Jim Sensenbrenner (R-Wis.).

Rep. John Ratcliffe (R-Texas), a former top federal prosecutor in the George W. Bush administration, made the case that Mueller’s report on Trump’s actions violated Justice Department guidelines meant to protect constitutional rights.

“The bedrock principle of our justice system is a presumption of innocence. It exists for everyone. Everyone is entitled to it, including sitting presidents,” Ratcliffe said.

Rep. Guy Reschenthaler (R-Pa.) said he believed the report “flies in the face of American justice” and said it was “un-American.”

Trump defenders have been at war with the FBI throughout his first term, and many of them raised concerns about the origins of the Russia investigation as well as private anti-Trump text messages traded by members of the FBI.

Reps. Matt Gaetz (R-Fla.), Jim Jordan (R-Ohio) and Louie Gohmert (R-Texas) all used their time to attack the Mueller investigation.

“You perpetuate injustice,” Gohmert yelled at Mueller.

Mueller, for his part, stressed that his investigation was meant to stay within certain bounds.

The “Office of Legal Counsel indicates that we cannot indict a sitting president, so one of the tools that a prosecutor would use is not there,” Mueller said.

“We made a decision not to decide whether to prosecute or not,” Mueller continued.

Mueller also took pains to avoid talking about impeachment, which he considered outside the scope of his job. He also said that a president could be charged with a crime after leaving office.

“We have studiously kept in the center of our investigation our mandate, and our mandate does not go to other ways of addressing conduct,” Mueller said.

Democrats insisted Wednesday that Mueller’s dry testimony before the House Judiciary Committee served their purposes and would educate more Americans about the contents of the Mueller report. Rep. Hakeem Jeffries (D-N.Y.) took issue with the suggestion that the president should be beyond the reach of the legal system.

“This is the United States of America. No one is above the law,” Jeffries said.