The core issue being debated before the Supreme Court on Thursday boils down to whether a former president is immune from prosecution for actions taken while in office. Never before has a former president faced criminal charges, so the court hasn’t had occasion to take up the question of whether the president’s unique role means he should be shielded from prosecution. Trump’s lawyers say presidents would be unable to function in office if they knew their actions in office could lead to criminal charges. Prosecutors say the lack of previous criminal charges “underscores the unprecedented nature” of what Trump is accused of.