The US Supreme Court takes up Tuesday the most politically charged case of the year -- President Donald Trump's refusal to turn over his tax returns and financial records to Congress and a New York prosecutor, a case that may define the limits of presidential immunity.

The high court's nine justices, confined at home by the coronavirus pandemic, will question lawyers for both sides at 10:00am (1400 GMT) by telephone in a highly anticipated session to be broadcast live.

The court's ruling, expected before the end of June, will allow the justices to render a decision before the November 3 presidential election in which Trump is seeking a second term in office.

The former real estate magnate is the first president since Richard Nixon in the 1970s to refuse to release his tax returns -- prompting speculation about his true worth and his possible financial entanglements.

Beyond Trump's case, the Supreme Court's decision will also have profound long-term implications for the balance of powers in the United States.

The president's lawyers maintain that during his time in office he effectively has complete legal immunity, which is necessary for him to focus on his work without being investigated by lawyers or members of Congress.

Several congressional committees and a Manhattan lawyer have issued subpoenas to Mazars, Trump's longtime accounting firm, as well as to Deutsche Bank and Capital One bank demanding the billionaire's financial records for the 2011-2018 period.

Trump immediately sued to block the release of the documents.

Since he lost his argument in the lower courts, Trump has turned to the nation's highest legal body. With two conservative Trump appointees on the nine-justice panel, the court has taken a clear turn to the right.

By agreeing to hear the case, the Supreme Court seems willing to change the prior legal decisions that could influence the firms' decision to surrender the president's records.

If the justices conclude that the issue is political in nature and not legal, they could determine that the courts were wrong to interfere. This would invalidate the previous rulings without ruling in Trump's favor. As a result, the three financial institutions would be free to send the documents to Congress -- or to refuse.