President Trump hit out against House Democrats and a federal judge on Monday in an appellate brief filed in the D.C. court of appeals, in the latest episode in his bid to halt a Congressional subpoena sent to accounting firm Mazars USA seeking years of his financial records.

Arguing that the demand for information “exceeds Congress’s investigative authority,” personal attorneys for the President contend that the House needs a legislative purpose to investigate Trump.

A federal judge upheld the subpoena — sent by House Oversight Committee Chair Elijah Cummings (D-MD) in April — in a blistering opinion last month. Trump immediately signaled that he would appeal.

In the brief, Trump repeats his argument that the requests constitute an invasion of his privacy.

“Yet replace ‘President’ with ‘Justices’ and the ruling below would, without question, authorize a congressional subpoena for the Justices’ accounting records— even for many years before they joined the Court,” Trump argues.

The President goes on to contend that even if the subpoena is found to have been issued for potential legislation, the House “could never show that the vast majority of documents it has subpoenaed from Mazars are pertinent to any stated legitimate aim.”

William Consovoy – a personal attorney for Trump – goes on to accuse the lower court of “invok[ing] the impeachment power on the Committee’s behalf.”

“That was remarkably inappropriate,” Consovoy writes, saying “the one thing the parties agree on is that this case is not about impeachment. The district court should not have suggested otherwise.”

Trump calls the House’s subpoena unprecedented, saying that “this Court has never seen anything like the current House.”

“The Committee claims sweeping authority to legislatively control the office of the President,” the filing reads, as part of an argument that the legislation Congress could contemplate on the issue would itself be unconstitutional.

Consovoy goes on to claim that the legislature’s power to oversee in part to inform the public is illegitimate as applied to the president. “Congress can ‘inquire into and publicize corruption, maladministration or inefficiency in agencies of the Government’ because a ‘legislative purpose is being served’ by those inquiries,” the filing reads, citing an earlier Supreme Court decision on the topic of Congressional subpoenas. “But that reasoning is inapplicable to the President.”

“Arming Congress with an ‘informing function’” where it lacks legislative power is what flouts ‘the Constitution’s design,’” Trump argues.

Trump launches into a broader argument that Congress is “severely constrained in the ways it can regulate the President.”

“Extending federal conflict-of-interest laws to the President (or imposing new ones on him) would exceed Congress’s narrow legislative authority over the office,” the filing reads.

The President also offers a description of the impeachment process, calling it “the most serious clash between Congress and the President contemplated by our Constitution,” adding that it “entails massive costs to our nation’s economy, national security, diplomacy, and political health.”

Consovoy concludes the brief by citing House Speaker Nancy Pelosi (D-CA). First, he approvingly cites her as being against impeachment, before concluding on the following note: “Speaker Pelosi has now admitted what this investigation is actually about: ‘I don’t want to see him impeached,’ she told senior Democratic leaders. ‘I want to see him in prison.’”

“It is difficult to imagine a clearer admission that the Committee has never been interested in legislating,” the brief reads. “It wants to see if the President broke the law.”

Trump sued to prevent his longtime accounting firm Mazars USA from complying with a subpoena from the House Oversight Committee in April. The lawsuit — paired with a similar case involving the President’s longtime lenders in Manhattan federal court — constitutes a nearly unprecedented attempt to prevent Congress from investigating Trump’s finances.

Read the filing here: