WASHINGTON — President Vladimir V. Putin of Russia authorized extensive efforts to interfere in the American presidential election to denigrate the candidacy of Joseph R. Biden Jr., including intelligence operations to influence people close to former President Donald J. Trump, according to a declassified intelligence report released Tuesday.
The report did not name those people but seemed to be a reference to the work of Mr. Trump’s former personal lawyer Rudolph W. Giuliani, who relentlessly pushed allegations of corruption about Mr. Biden and his family involving Ukraine.
“Russian state and proxy actors who all serve the Kremlin’s interests worked to affect U.S. public perceptions in a consistent manner,” the report said.
The declassified report represented the most comprehensive intelligence assessment of foreign efforts to influence the 2020 vote. Besides Russia, Iran and other countries sought to influence the election, the report said. China considered efforts to influence the presidential vote, but ultimately concluded that any such operation would fail and likely backfire, intelligence officials concluded.
A companion report by the departments of Justice and Homeland Security also rejected false allegations promoted by Mr. Trump’s allies in the weeks after the election that Venezuela or other foreign countries defrauded the election.
The reports, compiled by career officials, amounted to a repudiation of Mr. Trump, his allies and some of his top administration officials. They categorically dismissed allegations of foreign-fed voter fraud, cast doubt on Republican accusations of Chinese intervention on behalf of Democrats and undermined the allegations that Mr. Trump and his allies spread about the Biden family’s work in Ukraine.
The report also found that there were no efforts by Russia or other countries to change ballots themselves, unlike in 2016. Efforts by Russian hackers to probe state and local networks were unrelated to efforts by Moscow to influence the presidential vote.
The report also found more resilience among the American public and awareness of foreign efforts to spread disinformation. Intelligence agencies also credited social media companies with acting faster to remove fake accounts and spreaders of disinformation.
Still, foreign efforts to influence American politics remain a key threat, one the Biden administration has said it will fight.
“Foreign malign influence is an enduring challenge facing our country,” Avril B. Haines, the director of national intelligence, said in a statement. “These efforts by U.S. adversaries seek to exacerbate divisions and undermine confidence in our democratic institutions.”
Some of the intelligence report’s details were released in the months leading up to the election, reflecting an effort by the intelligence community to disclose more information about foreign operations during the campaign after its reluctance to do so in 2016 helped misinformation spread.
During the 2020 campaign, intelligence officials outlined how Russia was spreading damaging information about Mr. Biden’s son, Hunter, in an attempt to boost Mr. Trump’s re-election chances. It also outlined efforts by Iran in the final days before the election to aid Mr. Biden by spreading letters falsely purporting to be from the far-right group the Proud Boys.
Allegations of election interference have been some of the most politically divisive in recent years. The intelligence report is akin to an early 2017 declassified assessment that laid out the conclusions about Russia’s interference in Donald J. Trump’s electoral victory, further entrenched the partisan debate over Mr. Trump’s relationship with Moscow and cemented his enmity toward intelligence and law enforcement officials.
With Mr. Trump out of office and the new report’s conclusions largely telegraphed in public releases during the election, it was not expected to prompt as much partisan fury. But elements of it are likely to be the subject of political fights.
The conclusions about China are the most in dispute.
The declassified documents released Tuesday included a dissenting minority view from the national intelligence officer for cyber that suggested the consensus of the intelligence community was underplaying the threat from China.
In a letter released in January, John Ratcliffe, then Mr. Trump’s outgoing director of national intelligence, wrote in support of that minority view and said that the report’s main conclusions about China’s influence efforts “fell well short of the mark.”
Mr. Ratcliffe said the minority conclusion was more than one analyst’s view and argued that some intelligence officials were hesitant to label Chinese actions as influence or interference. Intelligence agencies were using different definitions of those terms, “potentially leading to the false impression that Russia sought to influence the election and China did not,” he said.
Privately, some intelligence officials defended the consensus view, saying their reading of the intelligence supported the conclusions that China sought some level of influence but avoided any direct efforts to interfere in the vote.
The assessment released Tuesday had the most detailed material about Russia. American officials see Russia as the clearest threat elections, given its track record.
Russia sought to influence how the American public saw the two major candidates “as well as advance Moscow’s longstanding goals of undermining confidence in U.S. election processes,” the report said.
Moscow used Andriy Derkach, a pro-Russian member of Ukraine’s parliament, to undermine Mr. Biden, the report detailed. Mr. Derkach, according to the report, released leaked phone calls to undermine Mr. Biden and link him to Ukrainian corruption four times in 2020. The report said Mr. Putin “had purview” over the actions of Mr. Derkach, who had ties to Russian intelligence.
Moscow’s operatives also pushed a false narrative that Ukraine, not Russia, was responsible for interfering in American politics, according to the report. Last year, American intelligence officials told Congress that Russia was using allies to pushing negative stories about Mr. Biden’s son Hunter and his work in Ukraine.
In the closing weeks of the election, intelligence officials said that Russian hackers had broken into state and local computer networks. But the new report said those efforts were not aimed at changing votes.
Unmentioned in this report was the massive hack of federal computer systems using a vulnerability in software made by SolarWinds. The absence of a concerted effort by Russia to change votes suggests that Moscow had refocused its intelligence service on a broader effort to hack the U.S. government.
Earlier in 2020, American officials thought Iran might likely stay on the sidelines of the presidential contest. But Iranian hackers did try a last-minute effort to change the vote in Florida and other states. Iranian operatives sent faked emails to voters, routing the messages through a Saudi insurance firm and Estonian textbook company to hide their origin.