A federal judge in Manhattan rejected an effort by US President Donald Trump and his adult children to send a lawsuit accusing them of exploiting their family name to promote a marketing scam into arbitration.
In a decision concerning the American Communications Network, Judge Lorna Schofield accused the Trumps of acting unfairly by seeking arbitration after first obtaining "the benefits of litigating in federal court", including the dismissal of a racketeering claim.
"This conduct is both substantively prejudicial towards plaintiffs and seeks to use the [Federal Arbitration Act] as a vehicle to manipulate the rules of procedure to defendants' benefit and plaintiffs' harm," she wrote.
Defendants included Trump's adult children Donald Jr, Eric and Ivanka, and an affiliate of the Trump Organisation. "We will take an immediate appeal," Joanna Hendon, a lawyer for the Trumps, said.
In the October 2018 complaint, the Trumps were accused of misleading victims into becoming salespeople for ACN, a multi-level marketing company that charged $499 for a chance to sell videophones and other goods.
According to the plaintiffs, the Trump family conned them into thinking Donald Trump believed their investments would pay off.
They said the real goal was for the Trumps to enrich themselves, including through the receipt of millions of dollars in secret payments from 2005 to 2015.
The Trumps have called the lawsuit politically motivated, and said Mr Trump's endorsement of ACN was merely his opinion.
Last July, Judge Schofield said the plaintiffs could pursue state law claims of fraud, false advertising and unfair competition against the Trumps.