Former president Donald Trump has offered to give House Democrats a peek at financial statements related to his complex business empire from before his 2016 presidential bid and eight years of contracts with his accounting firm, but refused to divulge more sensitive source data or internal communications, his lawyers told a federal judge Thursday.

The disclosure of the offer, made in late June in unsuccessful court-ordered mediation, came as Trump urged a federal judge in Washington to end a stalemate and toss out a 2019 House subpoena for eight years of his financial records, calling the congressional demand unconstitutional and unenforceable.

“The Committee on Oversight and Reform doesn’t need a decade’s worth of the former president’s sensitive financial information to legislate new financial regulations for all future presidents,” attorney Cameron T. Norris argued, saying lawmakers have plenty of power to gather data from other sources to overhaul disclosure rules.

The Post’s David Fahrenthold explains what we know about the charges against the Trump Organization and its CFO, Allen Weisselberg. (The Washington Post)

Trump is no longer president, but the threat to the separation-of-powers if the court rules otherwise remains, Norris said.

Enforcing the subpoena could unconstitutionally weaken every future president in dealings with Congress, raising the prospect that once he or she leaves office, lawmakers could compel and post for the world to see their most sensitive data, Norris said.

The fight over the subpoena for Trump’s records from 2011 to 2018 from accounting firm Mazars USA reached the Supreme Court last year, which ruled that congressional subpoenas seeking a president’s information must be “no broader than reasonably necessary” and returned the question to lower courts to work out the standard.

The battle is just one front in clashes over Trump’s tax information. After a separate Supreme Court ruling in March, Mazars turned over related documents to Manhattan District Attorney Cyrus R. Vance Jr. (D), whose prosecutors on Thursday charged the Trump Organization with a 15-year “scheme to defraud” the government and its chief financial officer with grand larceny and tax fraud.

House Democrats say they also need the information to amend financial disclosure and conflict-of-interest laws, saying Trump’s presidency posed historic threats of corruption. They cited the complex structure of his business, his failure to remove himself from management, refusal to release tax returns unlike his predecessors, and allegations by investigators that he gave inaccurate tax and other financial information.

The House sought the records after former Trump attorney Michael Cohen testified to Congress that Trump inflated and deflated certain assets on financial statements between 2011 and 2013 in part to reduce his real estate taxes.

Douglas Letter, general counsel for House Speaker Nancy Pelosi (D-Calif.), said Trump lawyers’ in mediation “never offered to produce a single document.” Instead they proposed that a handful of committee aides and lawmakers view a small sample of records in private; take notes instead of copy or photograph them; and keep the information confidential to the committee, Letter said. He called the limitations on reviewing complex and voluminous financial data “ridiculous.”

Trump lawyers accused the House of rushing to declare an impasse and asking U.S. District Judge Amit P. Mehta to rule summarily in its favor. But Letter said that Trump had run out the clock on one, two-year term of Congress, and could do so again “if we keep having … talks that go absolutely nowhere.”

Letter urged Mehta to respect the legislative branch’s powers, not only the president’s, and enforce the subpoena without looking into whether it was using it as a political weapon under the guise of legislation.

Mehta did not appear convinced, warning Letter that the Supreme Court has ruled Congress may not use presidents as “a case study” for general legislation.

“It seems to me Congress can turn to experts or to other people who have engaged in financial fraud,” “Why couldn’t you learn what you feel you have to learn by using somebody else’s financial documents,” Mehta said.

Letter responded that Trump created a singular “ethical crisis” that tested constitutional limits, and no fewer than eight related bills are pending this Congress.

“We need to study that … We need to know exactly how far we should go or not go with respect to disclosure requirements,” Letter said. “And that depends on our ability to find out how does someone like former president Trump, was he hiding things? How did he go about it? What was the extent of it, and can we fix it?”

After Mehta noted the Supreme Court emphasized that the legislative and executive branches should resolve disputes through negotiation or “accommodations” rather than through the courts, Letter said former presidents have turned over financial information. Letter said Richard Nixon released tax records about his children, Jimmy Carter about his business and Bill Clinton legal billing records of his wife, Hillary.

Mehta still sounded skeptical.

“Nothing is going to stop a future Congress from saying a future president has done something unprecedented, and seek an exiting president’s personal documents,” said the judge.

Letter said that prospect would be factored in to decision-making over the usual checks-and-balances between the branches of government and political parties, and he maintained that national security and conflict-of-interest concerns raised by Trump were unique.

Mehta asked if the House could narrow the subpoena — such as limiting it to records related to Trump’s ongoing voluntary lease with the federal government to operate his Trump International Hotel in Washington D.C., barring disclosure of compelled records, or requiring further mediation.

Norris said “history is on our side” on non-disclosure, saying Ronald Reagan’s Interior Department turned over subpoenaed documents for one day to lawmakers only with no copying and minimal notetaking. And, he said, the only two presidents subpoenaed by Congress — John Tyler and John Quincy Adams — testified confidentially for a potential impeachment of a cabinet official.

Regardless, the judge said “I am still not clear on what my authority is” if talks break down. “Is there anything I can do about that?” He added: ““I can’t cajole or jawbone” the sides.

Mehta promised to “work very hard to get everyone an expedited decision,” saying he knew any ruling would be appealed. “We know this is not the last stop. We’ll get it out in short order.”