While the House committee was deemed entitled to some of the records they sought from the accounting firm Mazars, the ruling could be seen as a setback for lawmakers since Mehta's 53-page ruling delved in detail into their need for the information ruled that the subpoena was not adequately tailored to serve those purposes.

Mehta said the committee's effort to get information on Trump's finances back to 2011 seemed to exceed its legitimate needs and threatened to intrude on presidential powers. The judge specifically discounted the panel's claims that it needed that data to determine whether Trump complied with a financial disclosure statute and whether that law should be changed.

"Due to its broad, invasive nature, the subpoena poses an appreciable risk to the separation of powers," wrote the judge, who was appointed by President Barack Obama. "In the current polarized political climate, it is not difficult to imagine the incentives a Congress would have to threaten or influence a sitting President with a similarly robust subpoena, issued after he leaves office, in order to 'aggrandize itself at the President’s expense....' In the court’s view, this not-insignificant risk to the institution of the presidency outweighs the Committee’s incremental legislative need for the material subpoenaed from Mazars."

Mehta was more receptive to the committee's claims that it needed access to Trump's financial data in order to assess whether he violated the Constitution's emoluments clauses by accepting payments from state or foreign governments and that the panel needed to audit the lease the General Services Administration granted to one of Trump's businesses in 2013 to build and operate the Trump International Hotel at the Old Post Office building on Pennsylvania Avenue in Washington.

The judge said the dealings related to the hotel were more akin to ordinary business transactions and he was hard pressed to see why Trump's ties to that deal should be off limits to investigation solely because he formerly served as president.

"By freely contracting with GSA for his own private economic gain, and by not divesting upon taking office, President Trump opened himself up to potential scrutiny from the very Committee whose jurisdiction includes the 'management of government operations and activities, including Federal procurement," Mehta wrote. "That he happened to occupy the presidency for some portion of his still-in-effect lease does nothing to change that fact."

House Oversight Chair Carolyn Maloney recognized the mixed nature of the judge's ruling and suggested the panel may appeal.

"Today’s district court opinion recognized that the Oversight Committee is entitled to a broad set of President Trump’s financial records as part of our critical investigation aimed at preventing presidential conflicts of interest, self-dealing, and constitutional violations," Maloney said in a statement. "While it is disappointing that the Court, despite finding that the entire subpoena served valid legislative purposes, narrowed the subpoena in some respects, the Committee is actively considering next steps.”

An aide to Trump vowed to keep up the the court battle. "We will be appealing, like we have been for about six years," the aide said.

The legal fight Mehta ruled on Wednesday has already made one trip to the Supreme Court. Last year, the justices rejected arguments from Trump's lawyers and the Justice Department that the courts cannot rule on subpoena battles between the legislative and executive branches. However, the ruling instructed lower courts to scrutinize Congress' need for the information and whether the subpoena fit those objectives.

The congressional demand has diminished in significance in recent months, due to Trump's loss and a parallel grand jury subpoena obtained by prosecutors in the Manhattan District Attorney's office. The Supreme Court also upheld the enforcement of that subpoena, leading to eight years of tax information being turned over to that office in February. That information fueled an indictment last month, charging the Trump Organization and its longtime Chief Financial Officer Allen Weisselberg with a variety of tax and fraud offenses.

Both have entered not guilty pleas.

While what the House panel would receive under Mehta's decision is just a subset of what the New York prosecutors already have, the committee has one option the prosecutors lack: Lawmakers would face few strictures on making the information public. The records turned over in New York are covered by grand jury secrecy, which limits public disclosure, but Congress isn't bound by those rules.

In a separate case before the court, Judge Trevor McFadden is weighing arguments over whether House Ways and Means Committee Chair Richard Neal should have access to six years’ worth of Trump’s returns. Neal says that he needs them so the committee can determine whether the IRS is doing an adequate job auditing presidents, something it has long done as a matter of policy.

Neal is citing an obscure law that allows the heads of Congress’ tax committee to examine anyone’s confidential tax information. Trump’s attorneys argue that Neal needs a legitimate legislative reason to get the returns, that he doesn’t have one and that Democrats simply want to hurt Trump politically.

The case has been moving through the court at a glacial pace, with preliminary legal wrangling now scheduled to drag into November.