A federal appeals court ruled Friday that President Donald Trump’s accounting firm, Mazars USA, must turn over eight years of his tax returns to the House Oversight Committee.The ruling is a significant blow to Trump’s efforts to stonewall Congress’s investigations into his businesses, financial dealings, campaign, administration, and personal life.House Democrats subpoenaed Mazars USA earlier this year, and Trump’s lawyers sought to block the subpoena, claiming Congress did not have a legitimate legislative purpose in seeking the president’s taxes.”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,” Friday’s ruling said.Friday’s development comes days after a federal judge ordered Mazars USA to turn Trump’s tax returns over to New York state prosecutors investigating whether the Trump Organization broke state laws.Visit Business Insider’s homepage for more stories.A federal appeals court ruled on Friday that President Donald Trump’s accounting firm, Mazars USA, must turn over eight years of his tax returns to Congress.The House Oversight Committee sent a “friendly subpoena” to Mazars USA earlier this year as part of a sprawling congressional inquiry into Trump’s businesses and financial dealings. In turn, Trump and several of his businesses sued Mazars USA, Cummings, and Peter Kenny, the chief investigative counsel for House Oversight Democrats, to block the subpoena. They claimed Congress had no legitimate legislative purpose for seeking the president’s taxes and that the subpoena was therefore invalid.On Friday, a three-judge panel on the United States Court of Appeals for the District of Columbia ruled 2-1 with House Democrats, saying the committee has the right to see Trump’s tax returns.”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,” the opinion said. “We conclude that the public record reveals legitimate legislative pursuits, not an impermissible law-enforcement purpose, behind the committee’s subpoena.”The judge who dissented, Neomi Rao, was appointed by Trump, according to The New York Times.Read more: A federal judge ordered Trump to turn over 8 years of his tax returns to New York prosecutorsFriday’s ruling comes days after a federal judge ordered Mazars USA to turn over eight years of Trump’s tax returns to New York state prosecutors investigating whether Trump and the Trump Organization broke state laws while facilitating hush-money payments to women alleging affairs with the president.Trump’s legal team can appeal Friday’s decision directly to the Supreme Court, and the president has indicated a willingness to do so in the past.Nonetheless, the ruling is a significant blow to Trump’s ongoing efforts to stonewall Congress’s investigations into his business, campaign, administration, and personal life.This also comes as the president faces a brewing congressional impeachment inquiry examining whether he used his public office for private gain. At the center of the inquiry are Trump’s repeated efforts to pressure the Ukrainian government to investigate former Vice President Joe Biden and his son, Hunter.A whistleblower complaint that a US intelligence official filed against Trump in August accused the president of abusing his power during a July 25 phone call with Ukraine’s president and soliciting foreign interference in the 2020 election. Trump has also been accused of potentially dangling US military aid to Ukraine as an incentive to get the country to probe the Bidens.Trump’s personal lawyer, Rudy Giuliani, was named 31 times in the complaint and described as a “central figure” in Trump’s efforts. Attorney General William Barr “appears to be involved as well,” the document said.On Thursday, the FBI arrested and charged two of Giuliani’s Ukrainian associates with campaign-finance violations. The Soviet-born men, Lev Parnas and Igor Fruman, took an active role in helping Giuliani dig up dirt on Biden and his son ahead of the 2020 election, prosecutors say.