Attorneys for the Democratic chairman of the House Oversight Committee said in court papers Wednesday that a lawsuit filed by President Trump aimed at blocking a panel subpoena was an attack on constitutional checks and balances and on Congress’s oversight powers..

In a 34-page answer to the lawsuit, filed April 22 by Trump against Chairman Elijah E. Cummings and Trump’s accounting firm, lawyers for Cummings (D-Md.) urged a federal judge to reject the president’s request to temporarily block the subpoena while the case proceeds.

Ruling for Trump “would directly impede ongoing congressional investigations of national importance and threaten the constitutional system that separates and divides power between the branches of government,” lawyers for the House panel wrote.

The result would overturn decades of court precedent and block probes into “numerous and serious constitutional, conflict of interest, and ethical questions raised by the personal financial holdings” of the president, they said.

The filing joins one fight in a many-sided legal battle between the Democratic-led House and the White House over the Democrats’ efforts to investigate various aspects of Trump’s life and business.

Congressional Democrats say the administration is stonewalling them, while Trump’s lawyers counter that they will not allow Democrats to wage a campaign of “congressional Presidential harassment.”

Last month, Cummings announced plans to subpoena Trump’s accounting firm, Mazars USA. The panel told Mazars that it is seeking documents to corroborate testimony of the president’s former lawyer, Michael Cohen, who told a congressional hearing that Trump intentionally misreported the value of his assets for personal gain.

In the lawsuit, Trump’s lawyers argued that the president’s past personal dealings are irrelevant to the legislative branch’s fundamental duty of writing bills and accused Democrats of overreaching.

“The Oversight Committee is . . . assuming the powers of the Department of Justice, investigating (dubious and partisan) allegations of illegal conduct by private individuals,” the president’s lawyers wrote.

Cummings’ attorneys called the lawsuit a long-shot bid to delay the unearthing of politically damaging information about Trump until after the 2020 election, and to obscure from the public ongoing conflicts of interest by officials charged with executing the nation’s laws.

“Trump’s attacks on the Committee’s investigations amount to nothing more than political histrionics and hyperbole,” they wrote, adding, “The Committee is exercising its oversight and investigative powers in a manner wholly consistent with Congress’s traditional purposes: to consider and enact legislation, oversee the administration of programs, monitor how taxpayer money is being spent, and inform the public,” they wrote.

In its own response Wednesday, Mazars attorney Henry F. Schuelke said the firm took no position on the case and did not ask to be heard at a May 14 hearing before U.S. District Judge Amit P. Mehta, saying, “Although Mazars USA is the recipient of the Committee’s subpoena, the dispute in this action is between Plaintiffs and the Committee.”