As Donald J. Trump tries to fend off lawsuits from angry home buyers, who claim he misled them about his role in developing luxury towers, his lawyers have repeatedly put forth a simple argument.

Purchasing agreements signed by the buyers, they contend, disclosed Mr. Trump’s role as a mere licensor who was paid for the use of his name — and contradicted marketing materials that suggested he was a developer.

On that basis, his attorneys said, a lawsuit filed against him in Florida should be tossed out.

Not so, a federal judge has ruled. 

On Monday, the judge, Adalberto Jordan of the Southern District of Florida, denied a motion from Mr. Trump’s lawyers to dismiss a major claim in a lawsuit filed by buyers of apartments in the Trump International Hotel and Tower Fort Lauderdale.

In his ruling, Judge Jordan said he was not persuaded by the arguments made by lawyers for Mr. Trump that “the purchase agreement contradicts the alleged misrepresentations made by Mr. Trump” and their argument that buyers had failed to show that such misrepresentations had been made.

“I find neither argument convincing,” he wrote.

After the Fort Lauderdale building ran into financial trouble, Mr. Trump exercised his right to terminate his licensing agreement and removed his name from the building, which remains empty and unfinished. Dozens of buyers lost hundreds of thousands of dollars in deposits, and they are now suing Mr. Trump, claiming he deceived them about his role.

In marketing materials, Mr. Trump called the Fort Lauderdale project “my latest development” and signed his name to letters announcing that “we have commenced construction” of the project.

Lawyers for Mr. Trump argued that the purchase agreements clearly stated who was the project’s developer — an entity called SB Hotel. But the judge found that the documents did not “state that SB Hotel is the sole developer or that the other defendants are not developers.”

“As a result,” he wrote, “this argument fails.”

In an e-mail in response to the ruling, Alan Garten, a lawyer for Mr. Trump’s company, said: “Trump was not the developer of the project and the fact that Mr. Trump had agreed to license his name was expressly disclosed in the purchase contracts which all buyers signed.”

He played down the importance of the ruling. “To be clear, Judge Jordan did not validate any of the buyers’ claims, but simply determined that the plaintiffs had satisfied the bare minimum pleading requirements to allow the case to go to the next stage — nothing more.”

Mr. Trump and his aides have complained about a May 13 story in The Times that touched on the Fort Lauderdale dispute and two similar cases, in Tampa, Fla., and Baja, Mexico.

On Wednesday, Mr. Garten said writing about Judge Jordan decision not to dismiss the case “shows just how biased and unethical a reporter you really are.”

In his decision, Judge Jordan noted that the defendants, including Mr. Trump, presented themselves as the team of developers behind the building.

“At times,” he wrote, “through advertising brochures, these defendants call themselves developers.”

A buyer, he wrote, “could have believed that alleged misrepresentation.”