"These are critical cases that are going to decide whether or not a president, in office, has presidential immunity for the duration of the time that he is sitting in office," said Claire Finkelstein, a criminal law expert at the University of Pennsylvania Law School and director of its Center for Ethics and the Rule of Law. "It would literally put the president above the law if the Supreme Court sides with the president's lawyers in this case," Finkelstein said.The outcome will also determine whether Trump -- the only modern American president to have not publicly released tax returns or divest from major business interests while in office -- has to share more personal financial information with voters before the November election.