It begins with dramatic music and slick graphics – skyscrapers, clouds, big screens, the roar of a helicopter and chants of “Four more years!” Then come clips of Donald Trump Jr mocking Barack Obama and Joe Biden, and hurling red “Keep America Great” caps into a crowd at a rally. A fireball darts across the screen, trailing the word “Triggered”.

Then, with slicked-back hair, designer stubble and a green-checked shirt unlikely to win any fashion awards, the president’s son hosts his own online show.

“Before the Covid-19 crisis brought to us by the wonderful communist Chinese government, who did nothing about it and lied to us,” Don Jr says, “we had the greatest economy … the greatest job numbers.

“I’m saying, the guy that did that once is the guy that can do it again. Not the 50-year Washington bureaucrat [Biden] who doesn’t remember where he is most of the time.”

Welcome to the virtual Trump campaign starring his three children, Don Jr, Eric and Ivanka, and their partners, Kimberly Guilfoyle, Lara Trump and Jared Kushner. The six are among the president’s most important surrogates and strategists, constantly pushing his cause, rallying his base, trashing his opponents and earning a reputation as a modern political mafia.

Some appear to relish the enterprise so much they are tipped to run for office themselves. Or, critics suggest, such is their devotion to amplifying Trump’s message – even when it contains ugly smears and downright lies – that perhaps they are merely competing for their father’s attention.

Last weekend Don Jr posted on Instagram a meme that falsely insinuated Biden is a paedophile, later insisting that he had merely been “joking around”, while Eric appeared to suggest Democrats created the virus to sabotage Trump’s campaign.

“And guess what?” he said on Fox News. “After 3 November [election day], coronavirus will magically all of a sudden go away and disappear and everybody will be able to reopen. They’re trying to deprive him of his greatest asset.”

At such moments, the Trump offspring can seem Trumpier than the man himself.

Moe Vela, a senior adviser to Biden when he was vice-president, said: “They are an extension of his divisive existence. The apple did not fall far from the hateful tree. They are hook, line and sinker a part of this fabricating, distortive, manipulative modus operandi.

“The kids are completely aligned with this complete distortion and disregard for the truth, whether it’s a conspiracy theory with ‘Obamagate’ or this paedophile comment or the most ridiculous one, that this pandemic is a hoax.

“Poor little Eric is clearly a low-IQ human being, but to say something like that when more than 90,000 families, sets of friends and co-parishioners have lost somebody that they loved, you have to be a horrible, despicable human being to even let that roll off your tongue, much less creep into your mind.”

Trump’s children have been ever present since he announced his wildly improbable run for the presidency at Trump Tower in New York in June 2015. A year later, Don Jr and Ivanka’s husband, Kushner, were present at a Trump Tower meeting with a Russian lawyer who promised dirt on Hillary Clinton. It came to nought but raised questions about the methods of both men.

Don Jr, Eric and Ivanka, along with Trump’s youngest daughter, Tiffany, were thrust into the limelight when they gave speeches at the 2016 Republican National Convention in Cleveland, where their father was crowned as the party’s nominee. In the second presidential debate, asked to name one positive thing about her opponent. Clinton replied: “Look, I respect his children. His children are incredibly able and devoted, and I think that says a lot about Donald.”

The children clocked up thousands of air miles campaigning while, behind the scenes, Kushner helped shape a crucial digital strategy. The family gathered with Trump on stage in New York when he stunned the world by winning. Since then, their influence has only grown.

Ivanka and Kushner – dubbed “Javanka” – are senior advisers at the White House, immune from the courtroom intrigue that has seen other officials purged at a record rate. Ivanka remains her father’s favourite: he has made the false and absurd claim that she had “created over 15m jobs”. Kushner’s almost comically sprawling portfolio has included criminal justice reform, a Middle East peace plan and, most recently, the coronavirus pandemic.

‘I learned it by watching you’

Don Jr and Eric stepped in to run the Trump Organization, the family business, where they have been forced to deny persistent allegations they are exploiting the presidency for profit. Both have also come into their own as bomb-throwers on their father’s behalf.

Before the virus hit, Don Jr was a regular speaker at rallies for Trump or Republican allies. A chip off the old block, he hits the same unsubtle notes as the president and hones and perfects his message: shorter, sharper, less digressive and potentially more deadly. A favourite line is to reference Obama’s 2016 claim that Trump would need a “magic wand” to bring back “some of those jobs of the past”. Don Jr spins this as a claim about economic growth and declares: “Well, abracadabra buddy. There is a magic wand for that!” The crowd invariably cheers.

In person and on Twitter, Don Jr has become expert in throwing red meat to the Trump base, in particular slamming Democrats and the media. Sometimes it’s a bit too much even for his dad. Don Jr told the Axios website in March about getting a call from the president: “‘You’re getting a little too aggressive, you know.’ And then I was like, ‘I learned it by watching you.’”

Two years ago, Don Jr separated from his wife, Vanessa, and began dating Guilfoyle, a lawyer, Fox News host and, incongruously, the ex-wife of Gavin Newsom, then the liberal Democratic mayor of San Francisco, now the governor of California. She joined the Trump campaign last year and has proved every bit as zealous as her boyfriend.

Eric is somewhat overshadowed by his brother but his wife, Lara, is now one of the most prominent figures in the campaign, regularly featuring in Women for Trump events and posting tweets such as: “The media tells us women don’t support Trump! WRONG!”

At a rally in Charlotte, North Carolina in early March, Eric and Lara delighted the crowd by inviting up to the podium a Trump supporter who had been camping outside the venue for four days. “I can’t believe this,” the woman said, sobbing tears of joy. It was political theatre that showed the family offers more than rage alone.

In the coronavirus pandemic, the children have hit the ground running in ways Trump and Biden have not. Trump’s re-election team broadcasts live programming online seven nights a week. This week it launched The Right View, including Guilfoyle and Lara Trump, as a riposte to the popular daytime show The View, which has an all-female panel.

Don Jr has also been highly active, holding virtual fundraisers and meetings with voters, attending pro-hunting events and recording calls and videos on behalf of candidates in the House and Senate. On Thursday night’s episode of Triggered (also the title of his first book), he interviewed the singer and guitarist Ted Nugent.

“I’m an outdoorsman, shooter, hunter, and not just, ‘I do one weekend a year to talk about it at a cocktail party for the next two years,’” said Don Jr, who has frequently admitted the irony of the son of a New York billionaire speaking on behalf of blue-collar Americans. “This is the way I choose to live my life when I’m not doing my day job.”

A moment later an advertising banner popped up: “Get your Trump-Pence 2020 playing cards!” Later, Nugent praised Trump Jr’s father for taking “a crowbar” to the political status quo: “He’s on a mission from God. This is divine intervention. We needed a status quo crusher and I can’t think of anybody except Donald J Trump that could have pulled it off with such effectiveness, such absolutism and, shall I say, aplomb.”

Up popped another banner that said: “Get your official I Heart Trump wine glasses!”

‘Extreme loyalty’

Democrats such as Vela, the former Biden adviser, find the Trump children and their partners as offensive as the president himself.

“You’ve got to sell your soul if you’re gonna be a part of it,” he said. “It’s almost like a mafioso operation, the mafia of hate. There is so much hate and hatred filled in their bones and in their hearts. I’ve never seen anything like it in my life.”

But for the president, the children form a protective shield.

Joshua Kendall, author of First Dads: Parenting and Politics from George Washington to Barack Obama, said: “The family is really important to Trump because he can get from them what he can’t get from most of the people who sign up to work with him: extreme loyalty. So he’s definitely going to lean on them and I think we’re witnessing a family tragedy because the children are all competing for who can be the most protective of daddy.

“It’s very disturbing, the extent to which they’re willing to go, and I guess the most chilling example was where Eric said that after the election we’ll find out that the whole Covid pandemic was cooked up by the Democrats. That’s the extent to which they’re willing to bend reality to stand up for their father. It’s also the tragedy of the Republican party that a lot of politicians are in this same position where in order to stay aligned with Trump, they have to bend reality.”

Presidential candidates’ children usually work behind the scenes, Kendall noted, pointing to the sons of Jimmy Carter in the 1970s and George W Bush in his father’s campaigns in 1988 and 1992.

“But what’s interesting about the Trump kids is they’re publicly playing the role of the hatchet man, which is usually played by the vice-president, famously Spiro Agnew [under Richard Nixon], and that’s not something we’ve seen before.”

The dynasty may yet continue. Signs such as “Don Jr 2024” and “Ivanka 2032” have been spotted at Trump rallies. A SurveyMonkey poll for Axios in January asked who Republicans would consider voting for in 2024. It was led by the vice-president, Mike Pence, but Don Jr was second, Nikki Haley third and Ivanka fourth.

Michael Steele, former chairman of the Republican National Committee, said: “There’s a lot of talk about that but I think the stark political reality that will hit them all, whether Donald Trump wins re-election or not, is that there are a whole lot of Republicans waiting in the wings for this administration’s transition to lame duck and they are not going to go quietly into that good night.

“It will not be, ‘Oh, you’re Donald Trump’s son or daughter so we bow and get out of the way.’ That ain’t happening.”