WASHINGTON (AP) — President Donald Trump is asking the Supreme Court to block a subpoena for his tax returns, in a test of the president’s ability to defy investigations.

The filing Thursday sets the stage for a high court showdown over the tax returns Trump has refused to release, unlike every other modern president. The justices also could weigh in more broadly on Trump’s claim that sitting presidents can’t be prosecuted or investigated for crimes.

He wants the court to decide the case by late June, under a deal to keep the Manhattan district attorney from enforcing the subpoena in the meantime. The returns are held by Trump’s accountants.

A second, similar case is headed to the court over a House committee subpoena demanding Trump’s financial records from the same accounting firm.