WASHINGTON — President Trump has to defend himself against claims that he’s been violating the Constitution by earning money from foreign sources while serving as America’s commander-in-chief, a court ruled Friday

The decision by the U.S. second circuit court of appeals marks a reversal of a lower judge’s ruling, and a breakthrough for those, including Congressional Democrats, who accuse Trump of breaching the Constitution’s so-called emoluments clause.

Trump will now have to submit his books and financial records to scrutiny by the plaintiffs suing him in this case, which include a national restaurant group and a Washington D.C. events planner, unless the Supreme Court or a wider assembly of judges reverse the decision.

Trump, the richest American president in history, has earned hundreds of millions while in office from his far-flung real estate empire, in what many Democrats view as a flagrant conflict of interest. Trump could’ve put the controversy to rest by fully relinquishing his business interests when he entered the White House. Instead, he handed over management to his adult sons through a trust, while continuing to receive updates about how the organization is faring.

Trump, meanwhile, continues to rake in the cash, including $421 million last year alone. If anything, he’s grown more brazen; recently suggesting that the next summit of the G7 group of wealthy democracies could be held at his golf resort in Florida.

On Tuesday, a top Senate Democrat asked the Pentagon to investigate Air Force travel expenses at Trump Turnberry golf course in Scotland, following a Politico report that personnel have been spending the night at Trump’s property while refueling at the nearby Prestwick Airport.

“I am disturbed by the growing number of those in government willing to engage in questionable taxpayer funded travel to and lodging at properties owned by the President — properties from which President Trump can draw income from at any time,” wrote Senator Gary Peters of Michigan in a letter to the Pentagon’s acting inspector general Glenn Fine.

Trump earned $23 million from his Scottish golf resort last year, according to his financial disclosure forms.

Trump’s hotel in D.C. has likewise been a hotbed of political controversy thanks to its popularity among foreign diplomats and lobbyists.

House Democrats have launched multiple investigations into Trump’s finances and subpoenaed his tax returns, while trying to uncover whether his decisions as president have been influenced by the possibility of foreign financial rewards.

Many of those probes are now tied up in legal disputes with Trump’s lawyers, meaning that even if Democrats eventually win, they might not be able to start digging through his financial records to look for evidence of foreign income or questionable business practices until after the 2020 election.