Supreme Court arguments have begun over whether former President Donald Trump can avoid prosecution over his efforts to overturn his 2020 election loss to Democrat Joe Biden.

The justices on Thursday took up for the first time whether a former president has absolute immunity from criminal charges for actions he took while in office, as Trump claims. He is the first former president to be charged with crimes.

Trump had said he wanted to be at the Supreme Court on Thursday. Instead, he was in a courtroom in New York, where he is standing trial on charges that he falsified business records to keep damaging information from voters when he directed hush money payments to a former porn star to keep quiet her claims that they had a sexual encounter.

The timing of the Supreme Court’s decision could be as important as the outcome. Trump, the presumptive 2024 Republican presidential nominee, has been pushing to delay the trial until after the November election, and the later the justices issue their decision, the more likely he is to succeed.

Special counsel Jack Smith’s team is asking for a speedy resolution. The court typically issues its last opinions by the end of June, about four months before the election.

Trump’s lawyers argue that former presidents are entitled to absolute immunity for their official acts. Otherwise, they say, politically motivated prosecutions of former occupants of the Oval Office would become routine and presidents couldn’t function as the commander in chief if they had to worry about criminal charges.

Lower courts have rejected those arguments, including a unanimous three-judge panel on an appeals court in Washington, D.C.

The election interference conspiracy case brought by Smith in Washington is just one of four criminal cases confronting Trump.

Smith’s team says the men who wrote Constitution never intended for presidents to be above the law and that, in any event, the acts Trump is charged with — including participating in a scheme to enlist fake electors in battleground states won by Biden — aren’t in any way part of a president’s official duties.

Nearly four years ago, all nine justices rejected Trump’s claim of absolute immunity from a district attorney’s subpoena for his financial records. That case played out during Trump’s presidency and involved a criminal investigation, but no charges.

Justice Clarence Thomas, who would have prevented the enforcement of the subpoena because of Trump’s responsibilities as president, still rejected Trump’s claim of absolute immunity and pointed to the text of the Constitution and how it was understood by the people who ratified it.