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.
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.
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.”