WASHINGTON — Robert S. Mueller III on Wednesday publicly rejected President Trump’s criticism that the special counsel’s investigation was a “witch hunt” and defended his conclusions about the sweeping Russian interference campaign in 2016, warning that Moscow will again try to sabotage American democracy.
The partisan war over his inquiry reached a heated climax during hours of long-awaited testimony by Mr. Mueller before two congressional committees. Lawmakers hunted for viral sound bites and tried to score political points, but Mr. Mueller refused to engage on those fronts, returning over and over in sometimes halting delivery to his damning and voluminous report.
Mr. Mueller remained a spectral presence in Washington over the past two years as the president and his allies subjected the special counsel and his team of lawyers to withering attacks. Speaking in detail for the first time about his conclusions produced occasionally dramatic moments where he ventured beyond his report to offer insights about Mr. Trump’s behavior.
When asked whether Mr. Trump “wasn’t always being truthful” in his written answers to the special counsel’s questions, Mr. Mueller responded, “I would say generally.” He called Mr. Trump’s praise of WikiLeaks during the 2016 campaign “problematic” and said it “gave a boost to what is and should be illegal activity.” He said that he and his team chose not to subpoena Mr. Trump out of concern that a battle over a presidential interview might needlessly prolong the investigation.
[Trump shared criticisms of Robert Mueller’s testimony and thanked Democrats.]
Democratic lawmakers had hoped that Mr. Mueller’s nationally televised testimony would provide a dramatic culmination to a yearslong saga: the special counsel translating the dense jargon of his report into a bleak portrait of the Russian interference operation and the president’s behavior since winning the election. The testimony would, in their minds, make the report both more authoritative and more vivid for Americans who had skipped reading it.
Some television pundits built up the drama by comparing Mr. Mueller’s appearance to some of the most galvanizing moments of the Watergate era.
For the most part, Mr. Mueller did not play along. He gave clipped answers to lengthy questions, and forced lawmakers to give their own dramatic readings of parts of his report rather than reciting the conclusions himself. He sometimes gave a forceful defense of his investigation and his team in the face of the Republican fusillade, but his answers were at times faltering. Throughout, he was careful to avoid straying from his report’s conclusions.
Mr. Trump has spent months characterizing the special counsel’s report as a “total exoneration,” though Mr. Mueller was careful on Wednesday to state that he and his team had drawn no such conclusion. The special counsel’s 448-page report, released in April, laid bare that Mr. Trump was elected with the help of a foreign power, and on Wednesday, Mr. Mueller was most impassioned when describing the contours of the Russian interference playbook.
“They’re doing it as we sit here,” he said of Russia’s tampering in American elections.
Looming over the hearing was the question of whether Mr. Mueller’s testimony might shift the ground in Congress and propel more lawmakers to push for Mr. Trump’s impeachment. Only one new call emerged for impeachment hearings by late afternoon Wednesday, from Representative Lori Trahan, Democrat of Massachusetts, and lawmakers will soon depart Washington for a summer recess. It was too soon to say whether the spectacle would change Americans’ opinions about Mr. Mueller and his work that have only hardened over time, and whether Democrats would return to their districts and encounter more vigorous calls for Mr. Trump’s removal.
The questioning on Wednesday reflected a bitter philosophical divide, both on the committees and in the country as a whole: whether it was Mr. Trump, or those investigating him, who committed crimes. Throughout the day, the Democrats hit the high points from Mr. Mueller’s report: the June 2016 Trump Tower meeting, the efforts by Mr. Trump to fire Mr. Mueller, the discussions between Michael T. Flynn and a Russian ambassador about Obama-era sanctions, the strategy by President Vladimir V. Putin of Russia to sow chaos before the election.
The Mueller report cataloged numerous meetings between Mr. Trump’s advisers and Russians seeking to influence the campaign and the presidential transition team — encounters set up in pursuit of business deals, policy initiatives and political dirt about Hillary Clinton, Mr. Trump’s 2016 Democratic opponent.
Mr. Mueller concluded that there was “insufficient evidence” to determine that the president or his aides had engaged in a criminal conspiracy with the Russians, even though the Trump campaign welcomed the Kremlin sabotage effort and “expected it would benefit electorally” from the hackings and leaks of Democratic emails.
On Wednesday, Mr. Mueller was asked about the Trump Tower meeting, WikiLeaks and the decision by Paul Manafort, the former Trump campaign chairman, to share campaign information with a Russian oligarch, and whether these episodes were a new normal for political campaigns.
“I hope this is not the new normal,” Mr. Mueller said, “but I fear it is.”
Republicans tried to flip the lens, peppering Mr. Mueller with questions about what they have long argued, with little evidence: that the F.B.I. opened a politically motivated investigation in 2016 with the aim of preventing Mr. Trump from becoming president. They focused on the research firm that commissioned the dossier by Christopher Steele, a former British intelligence officer. They focused on Joseph Mifsud, a Maltese academic identified by the special counsel as linked to Russian intelligence, and advanced unsubstantiated claims that Mr. Mifsud was actually under the sway of Western spy services.
Mr. Mueller mostly deflected those questions, saying the origins of the F.B.I. investigation predated his time as special counsel and was outside his purview.
Mr. Mueller was a reluctant witness and had tried to avoid the spectacle of a congressional hearing. In a brief public statement in May, he urged the public — and, by extension, members of Congress — to read his report, which he said “speaks for itself.” “The report is my testimony,” he said.
House Democrats were unmoved and chose to take the aggressive step of compelling Mr. Mueller’s testimony under subpoena.