WASHINGTON — A U.S. appeals court slapped down President Trump’s lawsuit to block his banks from sharing his records with House Democrats, placing Congress on the brink of unlocking the deepest secrets of Trump’s financial empire.

Tuesday’s decision hands Trump yet another stinging courtroom defeat as he scrambles to shield his family business from scrutiny by lawmakers and prosecutors, and increases the odds that Trump’s lockbox-like secrecy will shatter open before the 2020 elections.

The three-judge panel in Manhattan denied Trump’s suit to stop his longtime favorite lender, Germany’s scandal-plagued Deutsche Bank, from responding to subpoenas for his records from Democrat-led House committees, but issued a one-week stay pending an appeal to the Supreme Court.

Democrats believe Deutsche’s vaults contain a detailed map of Trump’s business empire, revealing how rich he really is, how he earned his money, any financial entanglements with foreign powers like Russia or Saudi Arabia, and, potentially, any signs of money laundering or other financial misdeeds.

Trump relied on Deutsche for billions in loans after a series of bankruptcies left him with a radioactive reputation on Wall Street. The German banking giant, which has suffered through a series of scandals over its role in helping launder vast amounts of Russian money and other embarrassments, cozied up to Trump and became his most important financial connection.

Democrats sent subpoenas to Deutsche Bank and another of Trump’s main banks, Capital One, earlier this year, but remain bogged down in Trump’s legal challenge to stop them.

Outside observers of the legal process say Trump appears destined for ultimate defeat in his multiple legal battles to stop Congress and New York prosecutors from accessing his business records and tax returns, but that he may be able to drag out the courtroom feuding well beyond the 2020 election. If that happens, Trump would escape the immediate political consequences of any damaging disclosures.

But it’s getting harder for Trump to run out the clock — especially after Tuesday’s ruling.

While Trump is all but certain to appeal this fresh loss to the Supreme Court, he’ll now need a robust defense from the high court in at least three separate cases, raising the odds of a final defeat in at least one sometime before November 2020.

Similar subpoenas seeking Trump’s financial documents by the House Oversight Committee and the Manhattan District Attorney are also lined up for possible decisions from the Supreme Court. Trump’s legal team hopes it can rely on the high court’s 5-4 conservative majority, including Trump-appointed justices Neil Gorsuch and Brett Kavanaugh, to protect him.

On Tuesday, the Second Circuit Appeals Court ruled in a two-three decision that Trump’s argument against disclosure lacked merit, though it found that a small number of categories of financial data, like medical reimbursements for members of Trump’s staff, might be off limits.

But Trump did receive a ray of hope from the dissenting third judge, Deborah Anne Livingston, an appointee of former Republican president George W. Bush.

Livingston called the Democrats’ subpoenas of Trump’s records “deeply troubling.” The vast scope of the requests, which target business and personal financial records for Trump as well as his family members, appears to extend beyond what would be necessary to assist Congress in developing new legislation, which is the nominal purpose of the subpoenas, the judge wrote.

But the majority decision on Tuesday (from two judges appointed respectively by Bush and former Democratic president Jimmy Carter), found that the public interest of disclosure to Congress outweighed any concerns that the suit might somehow be a mere nuisance case to harass Trump.

“The Committees’ interests in pursuing their constitutional legislative function is a far more significant public interest than whatever public interest inheres in avoiding the risk of a Chief Executive’s distraction arising from disclosure of documents reflecting his private financial transactions,” the judges ruled in their majority opinion.