Special Counsel Who Hunted for a Deep-State Conspiracy Presents Muted Findings

John H. Durham, the Trump-era special counsel who for four years pursued a politically fraught investigation into the Russia inquiry, told lawmakers on Wednesday that F.B.I. officials had exhibited confirmation bias — even as he defended his work against Democratic accusations that he became a partisan tool.

In a nearly six-hour hearing before the House Judiciary Committee, Mr. Durham rarely offered new information, repeatedly saying he did not want to go beyond his report. That approach echoed an appearance in 2019 before the same committee by Robert S. Mueller III, the special counsel overseeing the investigation into possible ties between Russia and the Trump campaign.

The hearing may be the final — official, at least — chapter in the complex saga of the Russia investigation and former President Donald J. Trump’s repeated efforts to reframe it as a deep-state plot, which has been a source of turbulence in American political life for more than six years. Mr. Durham retired after completing his report last month, and Senate Democrats have not invited him to testify.

For years, Mr. Trump and his allies stoked expectations that Mr. Durham would find a conspiracy lurking in the origins of the Russia investigation and would prosecute high-level officials. But Mr. Durham developed only two peripheral cases, both of which ended in acquittals, while citing flaws in the F.B.I.’s early investigative steps he attributed to confirmation bias.

“There were identified, documented, significant failures of a highly sensitive, unique investigation that was undertaken by the F.B.I.,” Mr. Durham said. “The investigation clearly reveals that decisions that were made were made in one direction. If there was something that was inconsistent with the notion that Trump was involved in a well-coordinated conspiracy with the Russians, that information was largely discarded or ignored.”

The hearing was largely a predicable display of partisanship, with each party trading claims about the merits of the underlying investigation into Russia’s attempt to manipulate the 2016 election in Mr. Trump’s favor. Mr. Mueller documented myriad links between Russia and Trump campaign officials, but did not charge any Trump associate with a criminal conspiracy with Russia.

Republicans railed against the Russia investigation as unjustified and portrayed it as politically motivated and corrupt, focusing on flawed wiretap applications and text messages in which F.B.I. officials expressed animus toward Mr. Trump.

Democrats defended it as legitimate and necessary by turning to the substance of Mr. Mueller’s work. Not only did he indict numerous Russians — and win convictions of multiple Trump associates on other crimes — but he also uncovered how the Trump campaign’s chairman had shared internal polling and strategy with a Russian and Ukrainian political consultant the government says is a Russian intelligence agent, among other things.

For large portions of the hearing, Mr. Durham served as a foil for both purposes, as lawmakers on each side asked questions intended to affirm whatever facts or claims they wanted to emphasize.

Much of his own critique of the investigation was familiar territory. The most factually grounded portions — especially errors and omissions in a set of wiretap applications that relied in part on claims in the so-called Steele dossier, a dubious compendium of what turned out to be opposition research indirectly funded by the Clinton campaign — echoed a December 2019 report by the Justice Department’s inspector general. Mr. Durham repeated those findings, but offered no concrete new suggestions for reforms.

Other parts were more ephemeral. After Mr. Durham’s initial effort to find intelligence abuses at the heart of the Russia investigation came up empty, he shifted to hunting for a basis to blame the Clinton campaign. He used court filings and his report to insinuate that the campaign set out to defraud the F.B.I. and frame Mr. Trump, although he never charged any such conspiracy. Some Republicans, however, treated that idea as established fact.

“What role did the Clinton campaign play in this hoax?” asked Representative Tom McClintock, Republican of California, adding, “Exactly what was the ‘Clinton Plan?’”

But some of Mr. Trump’s staunchest supporters expressed disappointment that Mr. Durham did not live up to the grander expectations that he would put high-level officials in prison and prove a deep-state conspiracy.

For example, Representative Matt Gaetz, Republican of Florida, insisted that suspicions about collusion between the Trump campaign and Russia emerged because of an operation by Western intelligence agencies — a conspiracy theory that Mr. Durham set out to prove but failed to find evidence to support. Mr. Gaetz said Mr. Durham had let the country down, and compared the special counsel’s inquiry to the Washington Generals, the basketball team whose job is to lose in exhibition games against the Harlem Globetrotters.

“When you are part of the cover-up, Mr. Durham, then it makes our job harder,” Mr. Gaetz said.

Mr. Durham replied that Mr. Gaetz’s comments were “offensive.”

But while most of the Republicans on the committee gave Mr. Durham a warmer welcome, he did not always say things that supported their position. Mr. Durham called Mr. Mueller a “patriot” and did not contradict any of his findings. He said that Russia did interfere in the 2016 election — and characterized that intelligence operation as a “significant threat.”

Pushed by Representative Mike Johnson, Republican of Louisiana, to go beyond his report’s conclusion that F.B.I. agents had acted with “confirmation bias” and accuse them in his testimony of having taken steps motivated by political favoritism, Mr. Durham demurred, saying that “it’s difficult to get into somebody else’s head.”

And he said that the F.B.I. had “an affirmative duty” to open some kind of investigation into the allegation that served as the Russia investigation’s basis — an Australian diplomat said that a Trump campaign adviser had made a comment suggesting that the campaign had advance knowledge that Russia would anonymously dump out hacked Democratic emails.

Still, he also testified that “in my view,” that information did not amount to “a legitimate basis to open as a full investigation” and that the bureau ought to have opened it as a lower-tier inquiry, like an “assessment” or a “preliminary” investigation. That went slightly beyond his report, which had argued that opening the inquiry at a lower level would have been better.

The Justice Department’s inspector general, Michael E. Horowitz, concluded in 2019 that the same information was a sufficient basis to open a “full” counterintelligence inquiry.

Throughout the hearing, Democrats pressed Mr. Durham to acknowledge or explain certain findings from a New York Times article in January examining how his inquiry became roiled by internal dissent and ethical disputes.

They asked him, for example, why his longtime deputy, Nora R. Dannehy, resigned from his team in September 2020. The Times reported that she did so in protest after disputes over prosecutorial ethics, including the drafting of a potential interim report before the 2020 election.

Mr. Durham spoke highly of Ms. Dannehy but declined to say why she had resigned. He called the Times article “unsourced” but did not deny its findings, adding, “To the extent The New York Times wrote an article suggesting certain things, it is what it is.”

Representative Zoe Lofgren, Democrat of California, asked Mr. Durham whether it was true, as the Times also reported, that when he and Attorney General William P. Barr traveled to Italy to pursue a certain pro-Trump conspiracy theory, Italian officials denied it but passed on a tip about unrelated financial crimes linked to Mr. Trump.

Mr. Barr decided the allegation, whose details remain unclear, was too serious to ignore but had Mr. Durham control an investigation into it, and he filed no charges, The Times reported.

“The question’s outside the scope of what I think I’m authorized to talk about — it’s not part of the report,” Mr. Durham replied, but added: “I can tell you this. That investigative steps were taken, grand jury subpoenas were issued and it came to nothing.”