A New York judge on Thursday is expected to rule on whether the Manhattan district attorney’s case against Donald J. Trump can go to trial as early as next month, in what would be the first criminal prosecution of a former American president.

The judge, Juan M. Merchan, will convene a hearing at 9:30 a.m. to address Mr. Trump’s long-shot request that he throw out the charges, which stem from a hush-money payment to a porn star. If Justice Merchan rejects Mr. Trump’s request — as is expected — then the judge will most likely set a firm date for the trial, which had been tentatively scheduled for March 25.

Mr. Trump, who is expected to attend the hearing on Thursday, faces 91 felony counts across four indictments from prosecutors in Washington, Florida and Georgia as well as Manhattan, all while he seeks to lock up the Republican presidential nomination.

The Manhattan district attorney, Alvin L. Bragg, was the first to obtain an indictment of Mr. Trump, accusing him last year of covering up a potential sex scandal involving the porn star during and after the 2016 election. Mr. Bragg, a Democrat, has cast his case not as a condemnation of sordid financial dealings, but as an example of Mr. Trump’s interfering in an election by concealing crucial information from voters.

Until recently, another criminal case involving accusations of election interference was poised to go to trial first. That case, filed in federal court in Washington by a special counsel, Jack Smith, centers on Mr. Trump’s effort to remain in power after his 2020 election defeat.