U.S. District Judge Amit Mehta in Washington said on Monday that the House Oversight and Reform Committee has authority to examine Trump’s personal and business records going back to 2011. The judge rejected Trump’s claim that Congress wasn’t entitled to the documents because they weren’t intended for a legitimate legislative purpose. The ruling is likely to be appealed.

“To be sure, there are limits on Congress’s investigative authority. But those limits do not substantially constrain Congress,” Mehta said in a 41-page ruling. “So long as Congress investigates on a subject matter on which ‘legislation could be had,’ Congress acts as contemplated by Article I of the Constitution.”

The ruling, if upheld on a likely appeal, would be the first to allow Congress to investigate the president’s finances, including his umbrella business, The Trump Organization. The information could challenge assertions he’s made about the amount and sources of his wealth.

Trump has been fighting to keep the information private since Democrats took control of the House in November. His lawyers have asked a federal judge to quash subpoenas for financial records from Deutsche Bank AG and Capital One Financial Corp., with a hearing set for May 22 in New York. Treasury Secretary Steven Mnuchin on May 17 refused demands for six years of the president’s tax records from the U.S. Internal Revenue Service, which may also spur a separate lawsuit.

Trump has refused to reveal the financial information since declaring his candidacy almost four years ago. After the 2016 election, rather than shedding assets or relinquishing family control, he placed his holdings in a revocable trust overseen by his sons and the Trump Organization’s chief financial officer, Allen Weisselberg. The president and his businesses filed suit in April to keep the House committee from obtaining records from Mazars, which has taken no position on the request.

At a May 14 hearing, Trump attorney William Consovoy had argued that congressional checks on the president were limited, which means oversight powers and enforcement of the Constitution’s emoluments clauses must be closely tied to a legislative function. Otherwise, Congress would take on a law-enforcement function reserved to the executive branch, Consovoy said.

Still, the lawyer demurred when asked by the judge how his claim squares with well-documented presidential probes such as Watergate and Whitewater. Consovoy said he’d need to look at the scope of those investigations.

Mehta, a 2014 nominee of President Barack Obama, also expressed doubt during the hearing about Consovoy’s claim that the judge must assess the constitutionality of any prospective legislation cited by the lawmakers as justifying their request. “I just can’t imagine that that’s what I’m supposed to do,” Mehta said.

Watergate, Whitewater

Committee attorney Douglas Letter argued that the president has taken the position that “Congress is a nuisance” and is getting in the way of his running the country. Letter called that notion “a total, basic misunderstanding of the Constitution.”

The committee doesn’t need a specific legislative objective to see the information it seeks from Mazars, Letter said, noting that Trump’s far-flung business holdings made such oversight a necessity. He also cited the Watergate and Whitewater probes as examples of Congress’ power to investigate and inform the public, along with investigations of the terrorist attacks of Sept. 11, 2001, and the justification for the Iraq war.

Asked whether any part of the president’s private life was off limits to Congress, Letter said the limit may lie at a request for something relating solely to Trump, such as a childhood diary or a sample of his blood, but perhaps not a mortgage application from 15 or 30 years ago.

The Mazars case is Trump v. Committee on Oversight and Reform, 19-cv-1136, U.S. District Court, District of Columbia (Washington).