A judge on Monday ruled that Donald Trump’s conviction for falsifying records to cover up a sex scandal should stand, rejecting the president-elect’s argument that it should be dismissed because of the US supreme court’s recent ruling on presidential immunity, a court filing showed.

Manhattan judge Juan Merchan’s decision eliminates one potential off-ramp from the case ahead of Trump’s return to office next month. His lawyers have raised other arguments for dismissal, however.

In a 41-page decision Merchan said Trump’s “decidedly personal acts of falsifying business records poses no danger of intrusion on the authority and function of the executive branch”.

Trump’s lawyer did not immediately respond to a request for comment.

Prosecutors have said there should be some accommodation for his upcoming presidency, but they insist the conviction should stand.

A jury convicted Trump in May of 34 counts of falsifying business records related to a $130,000 hush money payment to the adult film actor Stormy Daniels in 2016. The payment was for her silence before the 2016 election about a sexual encounter she has said she had a decade earlier with Trump, who denies it.

It was the first time a US president – former or sitting – had been convicted of or charged with a criminal offense.

The allegations involved a scheme to hide the payout to Daniels during the final days of Trump’s 2016 presidential campaign to keep her from publicizing – and keep voters from hearing – her claim of a sexual encounter. He says nothing sexual happened between them.

Trump pleaded not guilty and called the case an attempt by Bragg, a Democrat, to harm his 2024 campaign.

A month after the verdict, the supreme court ruled that ex-presidents can’t be prosecuted for official acts – things they did in the course of running the country – and that prosecutors cannot cite those actions to bolster a case centered on purely personal, unofficial conduct.

Trump’s lawyers then cited the supreme court opinion to argue that the hush money jury got some improper evidence, such as Trump’s presidential financial disclosure form, testimony from some White House aides and social media posts made while he was in office.

In his ruling, Merchan denied the bulk of Trump’s claims that some of prosecutors’ evidence related to official acts and implicated immunity protections.

The judge said that even if he found that some evidence related to official conduct, he’d still find that prosecutors’ decision to use “these acts as evidence of the decidedly personal acts of falsifying business records poses no danger of intrusion on the authority and function of the executive branch”.

Even if prosecutors had erroneously introduced evidence that could be challenged under an immunity claim, Merchan continued, “such error was harmless in light of the overwhelming evidence of guilt”.

Prosecutors had said the evidence in question was only “a sliver” of their case.

Steven Cheung, Trump’s communications director, called Merchan’s decision a “direct violation of the supreme court’s decision on immunity, and other longstanding jurisprudence”.

“This lawless case should have never been brought, and the constitution demands that it be immediately dismissed,” Cheung said in a statement.

The Manhattan district attorney’s office, which prosecuted the case, declined to comment.

Trump takes office 20 January 2025.