President Donald Trump asked the U.S. Supreme Court to hear his challenge to a House subpoena for financial records held by his accounting firm, saying lawmakers are exceeding their authority with a broad probe into his personal and business affairs.

The appeal comes in one of three subpoena cases speeding toward a potential Supreme Court showdown. The justices are already scheduled to discuss at their Dec. 13 private conference whether to take up Trump’s challenge to a subpoena by a New York prosecutor for his tax returns.

In addition, the president’s lawyers have said they will file an emergency request today asking the court to temporarily stop Deutsche Bank AG and Capital One Financial Corp. from handing over Trump’s financial records to the House.

The cases aren’t directly tied to the ongoing House impeachment probe, which centers on Trump’s push to have Ukraine announce investigations that could help him politically. The cases will test the justices’ willingness to shield the president from investigations into his personal and business affairs. Federal appeals courts ruled against Trump in all three disputes.

The Supreme Court has already temporarily blocked the House subpoena in the case that was the subject of Trump’s formal appeal today, involving the accounting firm Mazars USA.

‘All Statements’

The demand from the House Oversight and Reform Committee seeks “all statements of financial condition, annual statements, periodic financial reports, and independent auditors’ reports” in Mazars’s possession, as well as supporting documentation and related communications. It covers Trump’s individual finances as well as those of the Trump Organization over an eight-year period.

The panel says it wants the documents because it is considering revising the federal ethics-in-government laws. Trump’s lawyers say the primary purpose is law enforcement, something they say is beyond Congress’s legislative powers.

“This is a case of firsts,” Trump said in his new appeal. “It is the first time that Congress has subpoenaed personal records of a sitting president. It is the first time that Congress has issued a subpoena, under the guise of its legislative powers, to investigate the president for illegal conduct. And it is the first time a court has upheld any congressional subpoena for any sitting president’s records of any kind.”

In the New York case, Manhattan District Attorney Cyrus Vance Jr. is investigating whether Trump’s business falsified records to disguise hush payments to two women who claimed they had sex with Trump before he took office. In an appeal filed last month, Trump contended that presidents have broad immunity from criminal investigations while in office.

In the Deutsche case, two other House committees are seeking financial records for Trump, his children and the Trump organization. Those committees say they have a variety of legislative interests and are investigating money laundering, terrorist financing and Russian efforts to influence U.S. elections.