(Adds comment from Trump lawyer, details about subpoena and appeal)
By Jonathan Stempel
NEW YORK, Oct 7 (Reuters) - A federal judge on Monday said U.S. President Donald Trump must hand over eight years of tax returns to Manhattan prosecutors, forcefully rejecting the president's argument that he was immune from criminal investigations.
Trump's immunity claim was "repugnant to the nation's governmental structure and constitutional values," U.S. District Judge Victor Marrero wrote in a 75-page decision.
"The court cannot square a vision of presidential immunity that would place the President above the law," Marrero added.
Trump quickly filed an emergency appeal to the 2nd U.S. Circuit Court of Appeals in Manhattan, which temporarily blocked Manhattan District Attorney Cyrus Vance from enforcing the subpoena, citing the "unique issues" in the case.
Marrero's decision would have forced Trump's longtime accounting firm Mazars USA to start turning over documents on Monday afternoon.
The decision further complicates Trump's battle to keep his finances under wraps, despite having promised during his 2016 White House run that he would disclose his tax returns.
Vance, a Democrat, had subpoenaed personal and corporate tax returns from 2011 to 2018 and other records from Mazars, as part of a criminal probe into the president and his family business.
"The Radical Left Democrats have failed on all fronts, so now they are pushing local New York City and State Democrat prosecutors to go get President Trump," Trump, a Republican, tweeted after Marrero's decision. "A thing like this has never happened to any President before. Not even close!"
In suing Vance last month to block the subpoena, Trump argued that he was immune from criminal probes while in office, and the U.S. Constitution required Vance to wait until after he left the White House.
Trump is separately trying to block Deutsche Bank AG from handing over financial records, which the bank has said include tax returns, sought by multiple U.S. House of Representatives committees.
Those probes is separate from the debate over whether Trump should be impeached because of his dealings with Ukraine.
The 2nd Circuit appeals court heard oral arguments in the Deutsche Bank case on Aug. 23. It has yet to rule.
Jay Sekulow, a lawyer for Trump, said he was pleased the subpoena would not be enforced immediately. Danny Frost, a spokesman for Vance, declined to comment.
Both sides proposed schedules to allow oral arguments in Trump's appeal later this month.
Mazars did not respond to requests for comment, but has said it would comply with its legal obligations. The U.S. Department of Justice, which opposed Vance's bid to dismiss Trump's case, declined to comment.
Marrero, who was appointed by Democratic President Bill Clinton, declined to assert jurisdiction over the Vance subpoena, saying Trump should have brought his case in a New York state court.
The judge, however, made clear that if the appeals court disagreed with that finding, Trump should lose.
Marrero said Trump failed to show that enforcing the subpoena would interfere with his presidential duties, cause irreparable harm or be against the public interest.
He also rejected as too broad the idea that the president, his family and his businesses should be shielded from criminal process.
"The expansive notion of constitutional immunity invoked here to shield the President from judicial process would constitute an overreach of executive power," Marrero wrote.
Marrero said even President Richard Nixon had conceded during the Watergate scandal that he would be required to produce documents in response to a judicial subpoena.
In seeking a stay, Trump's lawyers said the case raised "momentous" questions about the president's immunity and that complying with the subpoena would cause irreversible damage.
"There will be no way to unscramble the egg scrambled by the disclosure," Trump's lawyers said.
Vance issued the subpoena four weeks after issuing another subpoena to the Trump Organization for records of hush money payments, including to two women prior to the 2016 election who said they had sexual relationships with Trump, which he denies.
Trump is running for re-election. His current term ends on Jan. 20, 2021. (Reporting by Jonathan Stempel in New York; Editing by Steve Orlofsky)