Congressional Republicans accused former Special Counsel Robert Mueller on Wednesday of operating under a double standard in his Russia investigation, alleging during a heated Hill hearing that Mueller threw the book at Trump associates while ignoring wrongdoing by others.

Republicans, for years, have attempted to draw a stark distinction between how the FBI and Mueller pursued allegations against President Trump and his campaign during the 2016 presidential election and how they reviewed alleged misconduct by prominent Democratic figures and those associated with them.

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On Wednesday, during the first round of Mueller’s testimony before the House Judiciary Committee, GOP lawmakers repeatedly confronted the former special counsel with that accusation -- with lines of questioning meant to illustrate a double standard.

At one point, Rep. Matt Gaetz, R-Fla., asked if he can say whether the controversial anti-Trump dossier “was not part of Russia’s disinformation campaign.”

“No – as I said in my opening statement, I-uh, I, that part of the ... building of the case predated me by at least 10 months,” Mueller replied.

Gaetz noted such reasoning did not stop prosecutors from going after Trump's former campaign chairman. “Paul Manafort’s alleged crimes regarding tax evasion predated you but you didn’t have a problem charging him,” he said.

Gaetz and Mueller went back-and-forth over the anti-Trump dossier, which was authored and compiled by ex-British intelligence officer Christopher Steele. The dossier was created on behalf of Fusion GPS—the firm that was hired to conduct opposition research funded by the Democratic National Committee and the Hillary Clinton campaign through law firm Perkins Coie. The dossier “formed an essential part” of the Foreign Intelligence Surveillance Act (FISA) warrants approved to surveil then-Trump campaign associate Carter Page, according to a House GOP memo alleging government surveillance abuse during 2016.

Gaetz complained Wednesday that concerns about Fusion and Steele were largely not in the report, and figures associated with them were not charged.

"When people associated with Trump lie, you throw the book at them. When Christopher Steele [lies], nothing," he said.

Mueller on Wednesday claimed he was “not familiar” with Fusion GPS, despite Steele’s reporting being referenced in his report. He also continued to state that the Steele matter is “beyond my purview.”

Gaetz fired back: “No -- that’s directly in your purview Mr. Mueller and here’s why. Either Steele made this whole thing up and there were never any Russians telling him of this vast criminal conspiracy that you didn’t find, or, Russians lied to Steele.”

MUELLER REFUSED TO DISCUSS RUSSIA PROBE ORIGINS, STEELE DOSSIER IN TESTIMONY

“Now if Russians were lying to Steele to undermine our confidence in our newly elected president, that would be precisely in your purview because you stated in your opening that the organizing principle was to fully and thoroughly investigate Russian interference. But you weren’t interested in whether the Russians interfered through Steele—and if Steele was lying, then you should have charged him with lying like you charged a variety of other people,” Gaetz continued.

The bulk of charges against Trump associates in Mueller’s investigation were based on false statements made either during the probe or to Congress. Six Trump campaign associates indicted in Mueller’s sprawling investigation were all charged with violating U.S.C. 1001—or making false statements.

They include former Trump campaign aide Rick Gates; former Trump personal attorney Michael Cohen; former Trump adviser Roger Stone; former White House national security adviser Michael Flynn; and former Trump campaign foreign policy adviser George Papadopoulos.

Rep. Jim Jordan, R-Ohio, directly questioned Mueller on his decisions to charge those “around the president” with false statements, and not several other key figures who played a central role in launching the investigation as a whole.

Jordan referenced Maltese professor Joseph Mifsud, who in 2016 told Papadopoulos that the Russians had dirt in the form of emails that could damage Clinton’s presidential campaign. Papadopoulos then told Australian diplomat Alexander Downer of the new information. Downer reported Papadopoulos’ comments to him to the FBI and effectively launched the bureau’s original investigation into the Trump campaign and coordination with the Russian government, according to reports.

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“Three times Mifsud lied to the FBI and you didn’t charge him with a crime. He lied three times—you pointed it out in the report—why didn’t you charge him with a crime?” Jordan asked.

Mueller replied: “I can’t get into internal deliberations with regard to who would or would not be--.”

“You charged a lot of other people with making false statements. Let’s remember this, in 2016, the FBI did something they probably haven’t done before. They spied on two American citizens associated with a presidential campaign—George Papadopoulos and Carter Page,” Jordan said. “With Page, they went to the FISA court and used the now-famous dossier to get a warrant. With Papadopoulos, they didn’t go to court—they used human sources—from the moment Papadopoulos joined the Trump campaign, you got people all around the world starting to swirl around him.”

Jordan went on to list Downer and Mifsud, among others.

“Mifsud is the guy who told Papadopoulos [about Russian dirt], he was the guy who started it all, yet when the FBI interviews him, he lies three times. You don’t charge him,” Jordan said. “The guy who starts the country through this saga—for three years we’ve been going through this now—he lies, you guys don’t charge him, and I’m curious to why.”

Mueller responded: “Well I can’t get into it and it’s obvious, I think, that we can’t get into charging decisions.”

“You can charge 13 Russians no one’s ever heard of, no one’s ever seen, no one’s ever going to see, you can charge all kind of people who were around the president with false statements, but the guy who launches everything—puts this whole show in motion—you don’t charge him. I think that’s amazing,” Jordan said.

“I’m not sure I agree with your characterizations,” Mueller said in an attempt to defend his report and team’s work.

“Well I’m reading from your report,” Jordan scoffed back.

The president, his surrogates, and Republicans on Capitol Hill since the start of the Mueller investigation have called for a separate probe into alleged misconduct at the FBI and with regard to the initial opening of its Russia counterintelligence review.

“Maybe a better course of action is to figure out how the false accusations started. Maybe find out why Mifsud was lying to the FBI—and here’s the good news—that’s exactly what Bill Barr is doing and thank goodness for that,” Jordan said.

Barr appointed U.S. Attorney from Connecticut John Durham to probe “all intelligence collection activities” related to the Trump campaign during the 2016 presidential election. Barr assigned Durham to also conduct the inquiry into alleged misconduct and alleged improper government surveillance on the Trump campaign, as well as whether Democrats were the ones who improperly coordinated with foreign actors.