Much at stake in Supreme Court fight over Trump's financial records

The U.S. Supreme Court is set to consider three blockbuster cases on Tuesday - all of them about President Donald Trump's long-sought financial records and whether or not they must be released before the 2020 election.

The trio of cases concern attempts by Democratic-led House committees and a grand jury working with New York City's District Attorney to enforce subpoenas seeking copies of the president's tax returns and other materials from three businesses: Trump's longtime accounting firm Mazars and two banks, Deutsche Bank and Capital One.

Investigators want the records to examine everything from possible tax crimes alleged by Trump's former lawyer Michael Cohen to whether or not Trump's dealings left him subject to the influence of foreign governments.

Carolyn Shapiro, the co-director of the Institute on the Supreme Court of the United States at the Chicago-Kent College of Law, says it's the biggest test of presidential power in decades.

"I think you can compare this case to the Nixon tapes case. But I think that case in some ways was more of an intrusion on the presidency than this case. In that case, there was a subpoena, a trial subpoena for tapes from the Oval Office... And he made a claim of executive privilege, which the Supreme Court said could not be upheld in that case. In many ways Nixon was a case that had a much stronger basis from the president to refuse to turn over what was being subpoenaed because it involved his actual official duties in the Oval Office... And in this case, we are the subpoenas seek only private records, records that have nothing to do with the conduct of the president in office. And in fact, he has not claimed executive privilege. He's claimed a variety of other reasons why he shouldn't have to turn them over."

Trump's lawyers argue that his financial records cannot be handed over because of his authority as president under the Constitution, pointing to Justice Department guidance that asserts that a sitting president cannot be indicted. In a lower court hearing, Trump's lawyers went so far as to argue that law enforcement officials would not have the power to investigate Trump even if he shot someone on New York's Fifth Avenue.

"The underlying principles that are at stake here really extend far beyond the current administration and that people who have a stake in maintaining our system of government, apart from which party is in power and apart from who is in the White House, believe it's very important to make sure that the president is not above the law."

Tuesday's oral arguments will be conducted by teleconference. The rulings from the nine justices are due by the end of June. In all three cases, lower courts in Washington and New York ruled against Trump.