In the bitter partisan war to discredit the Mueller investigation, Donald Trump’s allies have zeroed in on the Trump-Russia dossier compiled by Christopher Steele, accusing the F.B.I. of using the opposition-research document as the basis for its inquiry into the Trump campaign. The revelation that the Clinton campaign paid for part of the former British spy’s work—albeit indirectly, through the law firm Perkins Coie and Washington research firm Fusion GPS—fueled G.O.P. efforts to paint the Justice Department probe as biased from the start.

In recent days, however, the Republican narrative about the Trump-Russia investigation has begun to fall apart. On Tuesday, Fusion GPS founders Glenn Simpson and Peter Fritsch published an op-ed in The New York Times urging Republicans to release the transcripts of the more than 21 hours of testimony they provided to three congressional committees about the Steele dossier, arguing that withholding them has perpetuated falsehoods designed to protect the president. “Republicans have refused to release full transcripts of our firm’s testimony, even as they selectively leak details to media outlets on the far right,” Simpson and Fritsch wrote. “It’s time to share what our company told investigators.”

Simpson and Fritsch, both of whom previously worked as investigative journalists for The Wall Street Journal, stressed that the Steele dossier was not the impetus for the F.B.I. investigation into the Trump campaign. Per the Times:

We don’t believe the Steele dossier was the trigger for the F.B.I.’s investigation into Russian meddling. As we told the Senate Judiciary Committee in August, our sources said the dossier was taken so seriously because it corroborated reports the bureau had received from other sources, including one inside the Trump camp.

The intelligence committees have known for months that credible allegations of collusion between the Trump camp and Russia were pouring in from independent sources during the campaign.

A separate report published on Saturday seemingly corroborates Simpson and Fritsch’s account. Citing four current and former American and foreign officials with direct knowledge of the situation, the Times reported that a drunken admission by George Papadopoulos was a driving force behind the Justice Department’s decision to open an investigation into whether the Trump campaign coordinated with the Russian government. According to the outlet, in May 2016—three weeks after he was told Moscow had obtained thousands of emails damaging to Clinton’s candidacy—Papadopoulos informed Australian diplomat Alexander Downer that the Russians had compromising information on his boss’s chief rival in the presidential race. After the intelligence from Australia reached the F.B.I. in July 2016, law enforcement officials opened the counterintelligence investigation into the Trump campaign, the Times reports.

In their op-ed, Simpson and Fritsch also dismissed the narrative that their company’s past work with Natalia Veselnitskaya meant they were aware of the June 2016 Trump Tower meeting between the Russian lawyer and Donald Trump Jr., during which the latter sought damaging information on Clinton. “We first learned of that meeting from news reports last year—and the committees know it,” they wrote. “They also know that these Russians were unaware of the former British intelligence officer Christopher Steele’s work for us and were not sources for his reports.” And yet, the former journalists wrote, “Lawmakers in the thrall of the president continue to wage a cynical campaign to portray us as the unwitting victims of Kremlin disinformation.”

Those concerns are not unfounded. At the end of last month, it was reported that Congressman Devin Nunes is leading a select group of Republicans from the House Intelligence Committee in a parallel probe into the upper ranks of the Justice Department and F.B.I., and whether law enforcement officials mishandled the contents of the Steele dossier. Nunes, who was forced to step aside as chairman of the the House Intelligence Committee probe last year amid concerns that he released classified information to the White House, has been a vocal critic of the multiple Russia investigations and has stoked distrust of the F.B.I. “I hate to use the word corrupt, but they’ve become at least so dirty that who’s watching the watchmen? Who’s investigating these people?” Nunes said during an interview with Fox News last month, adding, “There is no one.”

But with key tenets of their counter-narrative beginning to crumble, and Democrats threatening to expose them for obstruction, Republican lawmakers could lose their toehold even as Mueller’s probe barrels on. “Flynn is cooperating, and that cooperation is likely to lead to further subjects or targets of the investigation,” Stephen Gillers, a professor of legal ethics at New York University, told The Wall Street Journal. “If this wraps up by the end of 2018, I’d be amazed.”