Lawyers clashed Tuesday in a Manhattan courtroom over whether a defamation lawsuit brought by a woman who has accused President Trump of unwanted sexual advances should be allowed to proceed in New York State Supreme Court.

The president’s lawyer, Marc E. Kasowitz, argued that the state court has no jurisdiction over a sitting president under the supremacy clause in the United States Constitution. He said the case should be dismissed or halted until Mr. Trump leaves office.

But Mr. Kasowitz faced sharp questions from Justice Jennifer Schecter, who noted there have been few — if any — legal decisions that address a state court’s ability to hear a case about a president’s actions outside of his official duties.

“This would be the first,” the judge asserted.

“This would be the first,” Mr. Kasowitz acknowledged.

The plaintiff in the lawsuit, Summer Zervos, is a former contestant on Mr. Trump’s show “The Apprentice.”