A hallmark of a successful disinformation campaign is adaptation — when proponents of the campaign adjust their tactics to get around efforts that journalists, government officials or tech companies have taken to stem its spread. On Oct. 16, campaign operators began adapting to Twitter’s curbs.

Finally, Mr. Trump tweeted the typosquatted hashtag the Friday before Election Day.

Over the last few weeks, posters have used adaptations of the slogan. There was #BidenCrimeFamilly, #BidenCrimeFamilyExposed, #BidenCrimeSyndicate.On Election Day, 17,000 people were posting about #BidenCrimeFamily on Facebook. On Twitter at midday, the slogan was being tweeted 3,500 times an hour.

Even though Parler or Gab did not censor the original hashtag, people posted the “ii” version of the hashtag there, too. Like all great memes, those who are in the know get it, while others assume it’s a dumb mistake.

An anonymous account with 52,300 followers tweeted a conspiracy theory using the "famiily" misspelling. Oct. 17 Another anonymous account tweeted using the “ii” hashtag, this time retweeting one of the banned Himalaya accounts. Oct. 18 Dinesh D’Souza, a far-right author, tweeted the typosquat. Oct. 19 Users on Reddit’s r/DeclineIntoCensorship subreddit and 4chan’s Politically Incorrect board noticed #BidenCrimeFamily had been de-indexed. Oct. 20 Users on thedonald also noticed the de-indexing. “Twitter doesn’t allow #BidenCrimeFamily - But you can get thru with #BidenCrimeFamiily - Notice the two i’s,” an anonymous user posted. Oct. 22 Actor Kirstie Alley tweeted the typosquat, adding two shruggie emojis.

While users could still tweet the hashtag #BidenCrimeFamily, Twitter stopped showing any results if the hashtag was clicked or searched. This strategy, called de-indexing, is a step short of censorship, and can be a powerful tool in reducing a hashtag’s ability to spread specific disinformation and to become a rallying place for coordinating action. Twitter did not respond to questions about this action.

The more people hear something, the more likely they are to believe it, whether it’s true or not. And false news can spread further and faster than the truth, especially on social media. Mr. Trump seems to understand this.

Marjorie Greene, a QAnon believer who was running for the House (and won on Tuesday), shared the hashtag and a meme on her Instagram account. Oct. 23 Giuliani used the phrase in an interview with the popular conservative radio host Dan Bongino, among others. All the while, Giuliani continued to tweet. Oct. 29 Fox Business host Lou Dobbs tweeted “Biden crime family” to promote an interview with Giuliani.

But since Oct. 14, conservative radio talk shows used the slogan in more than 150 broadcasts. One segment, from Larry Elder on Oct. 28, is simply titled, “The New York Post vs. the Biden Crime Family.” Conservative news outlets used the slogan in headlines. Pundits used it on TV. The phrase, repeated over and over, drilled into people’s heads the idea of Joe Biden’s corruption.

Despite the hashtag’s popularity on the right, it received little notice in the mainstream media. This is known as “hidden virality,” meaning something extremely popular in one part of the internet is going unnoticed by the mainstream news media.

On Oct. 16, The Daily Beast reported that these Himalaya accounts were a connected network affiliated with Mr. Bannon. Twitter confirmed to Foreign Policy magazine that it had taken down a network of connected accounts pushing Hunter Biden disinformation.

Many of these accounts are now suspended.

GNews pushed salacious conspiracy theories about Hunter Biden, with videos and photos. Twitter accounts with “Himalaya” in the handle used the #BidenCrimeFamily hashtag to spread those photos across Twitter.

People began tweeting #BidenCrimeFamily, accusing Twitter of censorship, and in some cases linking to another news site, GNews, that had also been pushing Hunter Biden disinformation.

The hashtag seeded itself on alternative social networking sites. It was popular on Parler, which advertises itself as a home for people censored by mainstream social media

In early October, Rudy Giuliani, the president’s personal lawyer, used the hashtag repeatedly,

As the Biden campaign picked up steam, the slogan started showing up more in the spring and summer of 2020 on talk radio and social media.

For more than a year, right-wing media and partisans have pushed “Biden crime family” as a viral slogan. Media manipulation campaigns are usually conjured in small, hidden spaces by a few operators with an agenda. But in this case, it was influential media and political personalities who got the ball rolling.

In any manipulation campaign, the second stage involves campaign operators strategically spreading the hashtag across the media ecosystem.

A reporter for One America News Network tweeted #BidenCrimeFamily to promote an interview about alleged “Biden Family Corruption.” Nov. 4 Sean Hannity said he thought there should be a criminal investigation opened up into Joe and Hunter Biden. Dec. #BidenCrimeFamily became a popular reply to posts about Trump’s impending impeachment. Feb. 10, 2020 Donald Trump Jr. told a crowd at a Trump rally in New Hampshire that his father was not like “the Biden crime family.”

Constant repetition makes the charge sound true, and blunts accusations of unethical behavior against Mr. Trump’s own children.

The hashtag took a complicated issue with legitimate questions about Hunter Biden’s business dealings with Ukraine and China — and reduced it to a slogan that could also be used to spread falsehoods about Joe Biden.

On Wednesday afternoon, with the presidential race unresolved, a protester in Nevada interrupted an election official’s news conference by yelling, “The Biden crime family is stealing the election!”

That moment wasn’t random. #BidenCrimeFamily is part of a yearlong, effective disinformation campaign against Joe Biden — one that was spread by social media, political influencers and the president himself.