Washington • President Donald Trump asked the Supreme Court on Thursday to bar his accounting firm from turning over eight years of his tax returns to Manhattan prosecutors.

The case, the first concerning Trump’s personal conduct and business dealings to reach the court, could yield a major ruling on the scope of presidential immunity from criminal investigations.

Last week, a unanimous three-judge panel of a federal appeals court in Manhattan ruled against Trump, rejecting his argument that he was absolutely immune from criminal investigation while he remains in office. The court, in a focused ruling, said state prosecutors may require third parties to turn over a sitting president’s financial records for use in a grand jury investigation.

Trump has fought vigorously to shield his financial records, and prosecutors in Manhattan have agreed not to seek the tax returns until the case is resolved by the Supreme Court. In exchange, they insisted on a very quick briefing schedule, one that would allow the Supreme Court to announce whether it will hear the case as soon as next month and to issue a decision by June, as the presidential election enters its final stages.

Other cases involving Trump are also in the pipeline. They involve matters as diverse as demands from House Democrats for tax and business records, a request for access to redacted portions of the report prepared by special counsel Robert Mueller, and challenges to Trump’s business arrangements under the Constitution’s emoluments clauses.

On Wednesday, the full U.S. Court of Appeals for the District of Columbia Circuit refused to rehear a ruling from a divided three-judge panel that Trump’s accounting firm must comply with the House Oversight and Reform Committee’s demands for eight years of his financial records. A lawyer for Trump said he would appeal that ruling to the Supreme Court, too.

The legal fight in the New York case began in late August after prosecutors in the office of the Manhattan district attorney, Cyrus Vance, a Democrat, subpoenaed Trump’s accounting firm, Mazars USA, for his tax returns and those of his family business dating to 2011.

The prosecutors are looking into hush-money payments made to two women just before the 2016 presidential election. Trump and his company, the Trump Organization, reimbursed his former lawyer and fixer, Michael Cohen, for payments he made to adult film actress Stormy Daniels, who claimed she had an affair with Trump.

Cohen was also involved in money paid to Karen McDougal, a Playboy model who also said she had a relationship with Trump. The president has denied the relationships.

Prosecutors say they need the documents to decide whether the payments violated state laws.

Trump’s lawyers sued to block the subpoena, arguing that criminal investigations of presidents are barred by the Constitution. They said sitting presidents are not only protected from being indicted, a proposition that is widely but not universally accepted, but also cannot be subjected to the burdens of criminal investigations, especially from local prosecutors who may use the criminal process for political gain.

When the case was argued last month before the 2nd U.S. Circuit Court of Appeals, Judge Denny Chin asked about a statement Trump had once made — that he could stand on Fifth Avenue and shoot someone without political fallout.

Chin asked William Consovoy, a lawyer for Trump, about the legal consequences of such a hypothetical crime.

“Local authorities couldn’t investigate?” Chin asked, adding: “Nothing could be done? That’s your position?”

“That is correct,” Consovoy said. “That is correct.”

In a footnote to last week’s decision, Chief Judge Robert Katzmann, writing for the appeals court panel, said allowing a grand jury to inspect tax returns did not seem likely to impose a burden on Trump’s ability to fulfill his constitutional responsibilities.

“We note that the past six presidents, dating back to President Carter, all voluntarily released their tax returns to the public,” Katzmann wrote. “While we do not place dispositive weight on this fact, it reinforces our conclusion that the disclosure of personal financial information, standing alone, is unlikely to impair the president in performing the duties of his office.”

Katzmann noted that Trump had conceded that his immunity would last only as long as he held office.

“There is no obvious reason why a state could not begin to investigate a president during his term and, with the information secured during that search, ultimately determine to prosecute him after he leaves office,” he wrote.