In 1787, the Framers gave us a president, not a king.

On Tuesday, lawyers for President Trump gave a dissenting opinion.

In the first of many courtroom showdowns between Trump’s executive branch and the legislative branch, Trump’s lawyer William Consovoy argued to U.S. District Court Judge Amit Mehta that Congress has no authority to pry into Trump’s finances. That was expected. Unexpected was Consovoy’s broader argument: that Congress has essentially no authority to investigate any president for anything. Sorry, Sam Ervin: Even the Watergate investigation would have been illegal under the theory offered by Trump’s team.

Consovoy, a former law clerk to Justice Clarence Thomas, offered two related points:

(A) Congress can’t issue a subpoena or otherwise probe a president unless it is doing so for a “legitimate legislative purpose.”

(B) Any “legitimate legislative purpose” Congress could conceivably devise would be unconstitutional.

As a result, Consovoy argued, Congress can’t investigate to see if a law is being broken, can’t inform the public of wrongdoing by the executive and can’t look for presidential conflicts of interest or corruption, because that would be “law enforcement.”

Forget about the unitary executive theory. This one is closer to the divine right of kings.

Mehta, an Obama appointee, probed for the limits of this breathtaking theory but found none:

Trump’s finances are not subject to investigation?

“Correct,” Consovoy informed the judge.

Congress can’t verify the accuracy of the president’s financial statements?

“Correct.”

If “a president was involved in some corrupt enterprise, you mean to tell me because he is the president of the United States, Congress would not have power to investigate?”

No, Consovoy said, because that’s “not pursuant to its legislative agenda.”

Consovoy, who is representing Trump as he tries to block the president’s accounting firm from fulfilling a subpoena from the House Oversight Committee for Trump’s financial records, further declared that Congress can’t investigate a president to inform the public of malfeasance (“the president is not an agency”), to see whether a president has a financial conflict of interest in a piece of legislation (“it would lack legitimate legislative purpose”), nor to discover whether financial conflicts impair a president’s ability to make sound policy (“that is law enforcement”).

But surely Congress could investigate a president’s compliance with the Constitution’s emoluments clause?

“I respectfully disagree in part,” Consovoy persisted, saying Congress can’t engage in “anything that looks like a law enforcement investigation.”

Even the Whitewater and Watergate investigations exceeded congressional authority?

Here, Consovoy demurred (“I’d have to look,” he said), rather than admit that his theory would have indeed banned both.

The Supreme Court has said judges shouldn’t look at Congress’ motives (even if they appear to be political) for investigating the executive, deferring to the legislature on what is a legitimate legislative function. But Consovoy told Mehta that “I don’t think the court can ignore” the Democrats’ motives, as expressed in public statements, and he called their legislative reasons “retroactive rationalizations.” Consovoy’s own argument sounded more political than legal at times. His brief began: “The Democrat Party … has declared all-out political war against President Donald J. Trump. Subpoenas are their weapon of choice.”

Consovoy’s argument was so aggressive, it seemed Trump’s lawyers expected defeat in the lower court and were looking for a higher court to reinterpret the law in Trump’s favor or, more likely, for the appeals to stretch until after the 2020 election. Consovoy sought delays for discovery and more arguments, saying it would be a disservice if “I did not go into depth.” But Mehta brushed off these attempts, saying he would close the record this week. And the judge flatly rejected Consovoy’s exotic argument that Mehta should pre-emptively declare unconstitutional any hypothetical legislation Congress might come up with related to its probe of Trump’s finances.

Douglas Letter, arguing for the House, said Consovoy’s position would require declaring unconstitutional “a whole batch” of laws that require disclosure by the president: the Ethics in Government Act, the Presidential Records Act and the Stock Act against insider trading.

At one point in the 90-minute argument, the judge asked Letter why the House wanted Trump’s private business records, because “this is not an impeachment proceeding.” And that’s the irony: As strong as the House’s oversight case is now, lawmakers would have more constitutional authority to demand information from Trump if they launched impeachment proceedings. Trump’s reckless legal argument is one more way in which he is goading the House to impeach him.

Dana Milbank is a columnist for The Washington Post. He can be contacted at:

dana.milbank@washpost.com