WASHINGTON — Mail-in voting for the November presidential election is safe from foreign intervention, intelligence and election security officials said on Wednesday, saying that standard security measures and decentralization make the United States’ election system extremely difficult for a foreign power to penetrate and change the results.
The assessment contradicts President Trump’s attacks on mail-in voting and comments by Attorney General William P. Barr that have also sowed doubt about its security.
The United States also has no intelligence that any nation-state is making a coordinated attempt to undermine absentee voting or create fake mail-in ballots, a senior official from the Office of the Director of National Intelligence said. The official and others briefed reporters on the condition that they not be named.
“We have yet to see any activity to prevent voting or to change votes, and we continue to think it would be extraordinarily difficult for foreign adversaries to change vote tallies,” the deputy attorney general under Mr. Barr, Jeffrey A. Rosen, said in separate remarks for the Center for Strategic and International Studies.
In July, and again this month, Mr. Trump raised the possibility, without evidence, that foreign adversaries would forge mail-in ballots and rig the election. He said the widespread use of mail-in and other absentee balloting was “going to be the greatest election disaster in history.”
“You guys like to talk about Russia and China and other places,” Mr. Trump said in July. “They’ll be able to forge ballots. They’ll forge them. They’ll do whatever they have to do.”
Raising the dubious prospect of forged ballots from Russia in particular contradicts Mr. Trump’s own deep skepticism of intelligence assessments that Russia interfered in the 2016 vote on his behalf, though there is no evidence that Kremlin operatives tampered with ballots.
Mr. Trump has more broadly stressed a difference between absentee and mail-in ballots — experts say they are interchangeable terms — and he and other administration officials have voted absentee. Critics accuse him of trying to undermine both mail-in voting and the post office because he believes expanded access to the ballot box is an advantage for Democratic candidates. (That may no longer be true.)
Mr. Trump has warned without evidence that mail-in voting makes fraud easier, and has suggested it could lead to a rigged result that wrongly denies him re-election.
Mr. Barr has also repeatedly raised concerns about the security of mail-in voting, as well as the threat of election interference. He told NPR News in June that he did not think an election conducted by mail-in vote could be secure.
Mr. Barr told lawmakers in July that he “had no reason to think” the November election would be rigged but said mail-in voting increased the risk of fraud. And he defended Mr. Trump’s claim that foreign governments could print fake mail-in ballots, saying that “it is not disinformation.”
Under further questioning he said he did not have evidence that foreign governments could sway American elections with fraudulent ballots but suggested it was common sense that they would try to do so.
But the officials speaking on Wednesday contradicted those assessments. An F.B.I. official said that the pandemic had created “a new environment” for voters to embrace mail-in ballots but that foreign governments would have great difficulty conducting coordinated voter fraud that could affect a national election.
The hyperlocal nature of ballots and elections is a natural barrier to fraudulent schemes, especially for national campaigns. Mail-in ballots are also scrutinized closely; they must be signed, and elections officials compare the signatures to those already in voters’ registration files.
Mr. Rosen said on Wednesday that foreign governments were, however, still trying to influence voters in other ways. Intelligence officials have outlined disinformation campaigns by Russia aimed at influencing the 2020 vote, and the State Department has detailed how Moscow’s intelligence services spread conspiracy theories.
“We do, however, continue to see malign foreign influence efforts,” he said.
Much of Mr. Rosen’s speech was a detailed history of attempts by foreign governments to influence elections, beginning with the contest between John Adams and Thomas Jefferson in 1796. In that race, France put information in a Philadelphia newspaper in an unsuccessful attempt to influence the election outcome.
“Malign foreign influence efforts in our elections have been a perennial problem,” Mr. Rosen said.
In recent weeks, William R. Evanina, a top intelligence official, has issued warnings about efforts by Russia, China and Iran to interfere in the election, including a stark admonition that Russia has spread disinformation about former Vice President Joseph R. Biden Jr. in an attempt to hurt his candidacy and lift Mr. Trump’s.
And top election security officials held a briefing with state election officials on Wednesday to update them on the latest threat reporting, including efforts by Russia, China and Iran to potentially influence election results.
The Department of Homeland Security and the F.B.I. have installed sensors on all state election computer networks as well as many local election systems to track any efforts by hackers to conduct reconnaissance or hack into voting systems, officials said.
The sensors have helped federal officials understand better the types of attempts to break into election systems. Most of the attempts have failed, according to homeland security officials, and largely amounted to efforts to find vulnerabilities that could be exploited later.
The Department of Homeland Security has been conducting tests and computer network security reviews, using information from those reviews and from the new sensors to develop warnings about vulnerabilities that hackers, including from foreign governments, could try to use before the election.
Some ransomware attacks on county governments have damaged election systems by locking them down, but those attacks were not aimed at halting voting, the federal officials said. They nonetheless prompted election officials to make adjustments.
Election security officials said they were worried about foreign influence operations not just before Election Day, but also in the days after, particularly if absentee voting creates delays in counting votes.
Federal officials will set up two operations centers to quickly address any problems, one for unclassified information and one for classified intelligence, that will begin functioning a week before the election and remain in place until local and state officials say the votes are counted. They will also set up a chat room for state and local officials to share information for a few days before and a few days after the election.