WASHINGTON — The Republican at the helm of the Senate’s investigation into Russian interference in the 2016 presidential election backed on Wednesday the assessment by American intelligence agencies that Moscow favored Donald J. Trump in the race, contradicting both the president and fellow Republicans in the House.
Senator Richard M. Burr of North Carolina, the chairman of the Senate Intelligence Committee, said in a statement that he saw “no reason to dispute” the intelligence assessment, which was delivered in the final weeks of the Obama administration.
Mr. Burr’s statement, while indirect, offered a clear rebuke to Mr. Trump’s most ardent supporters in the Republican Party and in the right-wing news media, who have sought to cast the assessment as the shoddy work of Obama loyalists bitter over Mr. Trump’s election victory. Russia’s only goal, those supporters have insisted, was to sow chaos, and thus it could not have colluded with a campaign it cared little about.
The only logical conclusion, they contend, is the one that Mr. Trump has already reached: The investigation led by Robert S. Mueller III, the special counsel, is a “witch hunt” cooked up by Democrats desperate to undermine a president they detest.
American intelligence officials, including Mr. Trump’s own appointees, who now run the agencies that compiled the assessment, say otherwise. They have repeatedly backed the work of their predecessors and sought to shield Mr. Mueller’s investigation from political attacks.
Asked at a Senate hearing on Wednesday if he stood by earlier statements that the special counsel’s investigation was not a witch hunt, Christopher A. Wray, the F.B.I. director, did not hesitate: “Yes,” he said.
And now, the intelligence assessment on Russia’s interference has the support of Mr. Burr, who said Wednesday that his committee was also continuing to investigate whether there was any collusion between Mr. Trump’s campaign and Russia. Examining the assessment was only the first step, the committee said.
“Committee staff have spent 14 months reviewing the sources, tradecraft and analytic work, and we see no reason to dispute the conclusions,” Mr. Burr said in the statement. “There is no doubt that Russia undertook an unprecedented effort to interfere with our 2016 elections.”
The Democratic vice chairman of the committee, Senator Mark Warner of Virginia, added, “The Russian effort was extensive, sophisticated and ordered by President Putin himself for the purpose of helping Donald Trump and hurting Hillary Clinton.”
The four main intelligence agencies — the Central Intelligence Agency, the National Security Agency, the F.B.I. and the Office of the Director of National Intelligence — compiled the assessment, and a declassified version was released Jan. 6, 2017. It said that all four agencies had “high confidence” that Russian spies had tried to interfere in the election on the orders of their president, Vladimir V. Putin.
The statements by top committee members on Wednesday came after the panel held a closed hearing with the men who led the intelligence agencies when the assessment was conducted, including John O. Brennan, the former C.I.A. director, and James B. Comey, the F.B.I. director fired by Mr. Trump.
The committee’s finding on Wednesday is the second of four interim conclusions that the panel plans to release before it issues its final report, which will most likely take place this year. This month, the committee released its findings on election security, concluding that Russian hackers surveilled around 20 state election systems and were looking for ways to undermine confidence in the United States’ voting process.
The Senate committee’s findings appear unlikely to give Mr. Trump much to crow about, unlike a parallel investigation by the House Intelligence Committee. That inquiry ended abruptly last month when the Republicans on the panel issued their own report, absolving the Trump campaign of aiding Russia’s election meddling and describing contacts between Trump associates and Russian officials or their intermediaries merely as ill-advised meetings.
The report, which ran about 250 pages, instead took aim at what Republicans called the misjudgments of Democrats and others, even as Republicans sought to play down the seriousness of mistakes by or suspicions about the Trump campaign. They faulted aides to Mrs. Clinton for secretly paying for opposition research that included information from Russian sources, and castigated federal law enforcement and intelligence agencies for failing to counter Russian interference as well as for purported investigative abuses and allegedly damaging national security leaks.
Mr. Trump breathlessly seized on the report, writing on Twitter: “‘No evidence’ that the Trump Campaign ‘colluded, coordinated or conspired with Russia.’ Clinton Campaign paid for Opposition Research obtained from Russia- Wow! A total Witch Hunt! MUST END NOW!”
Democrats on the committee joined the fray with a nearly 100-page dissenting document, denouncing the Republicans’ report as little more than a whitewash. They said that the Republicans showed no inclination to pursue even the most obvious of leads, and refused to interview crucial witnesses. The eagerness of Trump campaign aides to accept offers of Russian assistance, they said, suggested “a consciousness of wrongfulness, if not illegality.”
A third congressional investigation is being run by the Senate Judiciary Committee, which earlier on Wednesday released more than 2,500 pages of testimony and documents related to the June 2016 meeting at Trump Tower between campaign officials and a Russian lawyer supposedly there to deliver dirt on Mrs. Clinton.
Most participants in the meeting had already publicly shared their accounts, but the documents contained new details about the run-up to and aftermath of the meeting, including the fact that an associate of Donald Trump Jr.’s tried to set up a second meeting after the election.
At the same time, the release of the documents provided yet another reminder of the deepening partisan divide over Russia’s role in the election. Republicans on the Judiciary Committee pointedly declined to draw conclusions, instead describing the documents as “the most complete public picture” that would allow Americans to make up their minds about what had happened.
But Democrats sharply dissented, saying that the panel’s inquiry had been “limited” by Republican disinterest, and that too many questions remain unanswered to make conclusions.
Nicholas Fandos contributed reporting
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