WASHINGTON (Reuters) - A U.S. appeals court said on Wednesday it would not revisit an October decision backing a U.S. House of Representatives subpoena issued to President Donald Trump’s accounting firm for his financial records.

U.S. President Donald Trump speaks during a joint news conference with Turkey's President Tayyip Erdogan at the White House in Washington, U.S., November 13, 2019. REUTERS/Tom Brenner

The 8-3 vote by the U.S. Court of Appeals for the D.C. Circuit, declining the Republican president’s request to rehear arguments that the subpoena to Mazars LLP was illegitimate, brings Democrats closer to shedding light on his business interests and how he built his fortune.

In a statement, Trump lawyer Jay Sekulow said the president would appeal to the U.S. Supreme Court.

The House Oversight Committee subpoenaed Mazars this year, saying it needed the records to determine if Trump complied with laws requiring disclosure of his assets, and to assess whether those laws needed to be changed.

While campaigning for the presidency in 2016, Trump broke with a decades-old convention of candidates releasing their tax returns publicly.

Trump sued the House panel in April, arguing that its subpoena exceeded limits on Congress’s investigative power.

He said the true motive for the subpoena was to expose private financial information “with the hope that it will turn up something that Democrats can use as a political tool against the President.”

A lower court judge ruled against Trump in May, saying the documents might assist Congress in passing laws and performing other core functions.

The May decision was the first time a federal court waded into the tussle about how far Congress can go in investigating Trump and his business affairs, and marked an important victory for House Democrats.

A three-judge panel of D.C. circuit judges, in a 2-1 ruling, upheld the lower court judge in October.

“Contrary to the president’s arguments, the committee possesses authority under both the house rules and the constitution to issue the subpoena, and Mazars must comply,” Judge David Tatel wrote on behalf of the majority.

Judge Neomi Rao, who was appointed by Trump to the D.C. appeals court, dissented from the October decision.

Rao and another Trump appointee to the court, Gregory Katsas, voted to rehear the case, Wednesday’s order showed. They were joined by Karen Henderson, an appointee of former President George H.W. Bush.