President Trump and three of his adult children have been hit with a racketeering lawsuit — filed in Manhattan federal court just a week before the midterm elections — claiming they “conned” vulnerable people to sink their hard-earned cash into sketchy multilevel marketing schemes while Trump was pocketing millions in “secret payments” for his endorsement.

The lawsuit, which names the president as well as children Ivanka, Don Jr. and Eric Trump, is being brought on behalf of four unnamed “working-class Americans” who say they lost money in one of the ventures — and is being bankrolled by a nonprofit whose chairman is a Democratic donor and outspoken critic of the president.

The suit, filed in Manhattan federal court on Monday, alleges the president and his organization “deliberately misled” consumers by using Trump’s image as a successful businessman to encourage consumers to buy into three get-rich-quick schemes, despite knowing they weren’t good investments.

“Indeed, defendants were aware that the vast majority of consumers would lose whatever money they invested in the business opportunities and training programs the endorsed entities offered,” the suit reads.

Between 2005 and 2015, Trump appeared regularly as a pitch man for one of the outfits, telecommunications reseller ACN while insisting his backing was not “for any money,” the suit alleges.

But in fact, he was being rewarded handsomely for appearing at its events, in marketing materials and for promoting the company on “The Apprentice,” it charges.

One of the plaintiffs, named in the suit as Luke Loe, was homeless when he saw a video promoting ACN that heavily featured Trump and borrowed the $499 required to become a salesman for the scheme “based largely on Trump’s endorsement,” the suit claims.

Unable to sell much in the way of services or recruit many other sellers, he borrowed even more money to attend ACN conventions and other events hoping they’d help him recoup his investment, but he eventually gave up without any income to show, the suit charges.

The suit is being financed by a nonprofit called the Tesseract Research Center, whose chairman, Morris Pearl, has donated to Democratic candidates, according to the New York Times.

Pearl is a former executive at investment firm BlackRock who has been a vocal critic of Trump’s tax cuts.

A Trump Organization lawyer said the allegations were without merit and the suit was obviously politically motivated.

“This is clearly just another effort by opponents of the President to use the court system to advance a political agenda,” attorney Alan Garten told the Times.

“Their motivations are as plain as day.”

But lawyers for the plaintiffs told the paper the timing of the legal action is just a coincidence.

“The case is being brought now because it is ready now,” the lawyers said.