When the nation’s top intelligence officials last spoke publicly together, in January of last year, they said that foreign adversaries were eyeing the 2020 elections as an opportunity to launch “online influence operations” that seek to undermine public confidence in democratic institutions and influence public opinion in the United States.

Now, the storm that the officials forecast in their annual 2019 Worldwide Threat Assessment is bearing down on the final phase of the presidential campaign, according to U.S. officials and experts.

At least three countries — Russia, China and Iran — have taken aim at the campaigns themselves and tried to stir the passions of voters, with a mix of covert “information laundering” and some ham-handed propaganda.

Russia may pose the most direct challenge to this year’s election. Officials and experts also say it has reprised its 2016 seeding of social media with misleading content and is trying to amplify stories in the U.S. press that cast former vice president Joe Biden in a negative light, officials and experts say.

An exhaustive bipartisan Senate report issued Tuesday revealed in disturbing detail the extensive web of contacts between Kremlin operatives and Trump campaign members in 2016 as Moscow attempted to sway the election in Trump’s favor, and noted that Russian President Vladimir Putin personally directed the hack-and-leak campaign aimed at damaging Democratic candidate Hillary Clinton.

Russia may not have to work as hard this time to undermine voter confidence. On a near-daily basis, President Trump asserts, falsely, that mail-in voting is rife with fraud and insists that if he loses it will be the result of unprecedented corruption.

In a recent broadside, Trump said he opposes election aid for states and an emergency bailout for the U.S. Postal Service because he wants to restrict how many Americans can vote by mail.

A senior intelligence official said this week that his concern is potential interference efforts after Election Day when a surge in mail-in voting delays a final outcome. “We need to prepare as a nation that the election will not be decided on November 3,” William Evanina, the top counterintelligence official in the Office of the Director of National Intelligence (ODNI) said during an online session sponsored by the U.S. Chamber of Commerce.

“I’m frankly more concerned about domestic players this time around,” said Bret Schafer, who studies disinformation at the Alliance for Securing Democracy at the German Marshall Fund of the United States.

ODNI has spoken to lawmakers and the campaigns on the landscape of threats and has provided nearly 20 classified briefings.

Officials familiar with the intelligence said that many of the techniques are familiar. But the persistence and pervasiveness of the foreign efforts is alarming, the officials said.

“The warning lights are flashing red. America’s elections are under attack,” Sen. Richard Blumenthal (D-Conn.) wrote in a Washington Post editorial earlier this month.

On Aug. 7, Evanina publicly stated for the first time that Russia was using “a range of measures to primarily denigrate former vice president Biden and what it sees as an anti-Russia ‘establishment.’ ” China, meanwhile, wants “to shape the policy environment in the United States,” Evanina said, and has deployed more-rhetorical methods. China would prefer that Trump lose in November, finding him “unpredictable,” Evanina said. But the country hasn’t actively taken a side in the race.

Evanina described Iran’s efforts as undermining democratic institutions and Trump, but they appear aspirational compared to those of Russia and China. Iranian and Chinese hackers have attempted to penetrate the Gmail accounts of staffers for the Trump and Biden campaign, but there were no indications they were successful, Google announced in June. And it’s not clear that the efforts were preludes to a release of emails aimed at disrupting the campaign, as happened in 2016.

“Many foreign actors have a preference for who wins the election, which they express through a range of overt and private statements; covert influence efforts are rarer,” Evanina said.

It would be wrong and shortsighted to equate the three countries’ activities, experts said.

“It isn’t fair to treat China, Russia and Iran as functionally similar,” said Darren Linvill, a professor at Clemson University who studies social media and propaganda.

Most Chinese disinformation is “defensive” and focuses on issues that are important to the government, Linvill said. “It often seems to be about saving face,” such as when Houston Rockets General Manager Daryl Morey’s Twitter account was flooded with pro-China comments after Morey tweeted in support of anti-government protesters in Hong Kong.

This month, new research from Graphika, a social media analysis company, showed that a network of fake Chinese accounts has been posting videos bashing Trump, criticizing his recent closure of China’s consulate in Houston, his handling of the coronavirus pandemic and his threats to ban the popular social media app TikTok.

The researchers also found the first direct reference to Biden — a bunch of flattering pictures — from the Chinese network, which has a history of rapidly churning out videos with awkwardly worded English subtitles and narration. The group hasn’t been directly linked to the Chinese government and it isn’t clear whether the intended audience for the videos was Chinese, American or a combination. But its overarching goal seems to be defending Chinese interests, which is in line with the U.S. intelligence assessment.

Compared with China, Russia plays offense. “They try to influence conversations that aren’t of inherent interest to Russia, but through which they want to hurt the West,” Linvill said. “This includes . . . race, immigration, gender and gun ownership.”

Whereas China will often use stolen social media accounts with random followers or bots that have no followers at all, Russia creates accounts aimed at particular issues that work to attract real followers.

“Their accounts are artisanal and their messages are carefully crafted for that specific audience,” Linvill said. “They have built up a remarkable ability to engage culturally.”

As for Iran, “they often try to mimic Russia, but they aren’t as good at it,” Linvill said.

So far in the 2020 campaign, officials said they hadn’t seen Russia attempt to repeat its hacking and dumping of emails. But the country is spreading disinformation via social media and the press, including through a network of proxies and websites, the State Department found in a detailed report released this month.

Some websites promoting pro-Russian or anti-U.S. stories have clear links to Russia, such as Ruptly, which is owned by the Kremlin-backed media network RT. But others keep their connections hidden. The news agency InfoRos, for example, which has recently run articles critical of Biden and his process of selecting a running mate, is linked to Russia’s military intelligence agency, the GRU, said Western intelligence officials who spoke on the condition of anonymity to discuss intelligence assessments.

Schafer said Russia has moved away from flooding social media with stories and memes. “If you place a breadcrumb in the far reaches of the Internet on a website, it doesn’t need to generate traffic on its own. It just needs to land on the radar of an outlet that is real or run by Americans.”

The Russians also have enlisted foreign agents to trickle disinformation into the media bloodstream. Evanina confirmed that Russia had used a pro-Russian lawmaker from Ukraine “to undermine former vice president [Joe] Biden’s candidacy and the Democratic Party.”

The lawmaker, Andriy Derkach, met in December with Rudolph W. Giuliani, Trump’s personal lawyer, as part of an effort by Trump’s allies to obtain damaging information about Biden in Ukraine.

Derkach previously told The Washington Post that he had sent information to the Senate committee chaired by Ron Johnson (R-Wis.), who is conducting his own investigation into Biden and Ukraine, despite warnings from Democrats and intelligence experts that he risks laundering Russian disinformation through the Senate.

“U.S. intelligence is once again fighting the Russians with a hand tied around their backs, as some members of the GOP are in fact deliberately and inexplicably siding with our enemies by using Russian disinformation to try to damage candidate Biden,” said Marc Polymeropoulos, a retired CIA officer who oversaw operations in Europe and Russia, singling out Johnson.

Johnson has defended his investigation, which he has said he hopes to make public next month. His spokesman has denied that the committee received material from Derkach.

Some experts question the utility of propaganda at a time when American voters are already polarized.

Russia doesn’t have to work hard to stoke Americans’ emotions “because we’re doing a whole lot of it ourselves,” said Laura Rosenberger, the director of the Alliance for Securing Democracy.