The White House’s position on Congress’s authority to investigate President Trump, it seems, is that it has none. A federal judge practically laughed at Trump’s attorney Monday when he made that argument, but White House counsel Pat Cipollone has now doubled down.

“Congressional investigations are intended to obtain information to aid in evaluating potential legislation,” Cipollone wrote to House Judiciary Committee Chairman Jerry Nadler (D-N.Y.) on Tuesday, “not to harass political opponents or to pursue an unauthorized ‘do-over’ of exhaustive law enforcement investigations conducted by the Department of Justice.”

The defiant letter is the culmination of weeks of the White House saying it wouldn’t comply with basically any subpoenas from the Democratic-controlled House. You can’t do that without making some kind of legal argument as to why, of course. Apparently the White House has landed upon saying Congress can’t investigate anything the president does unless it pertains to legislation.

That kind of precedent would lead to a whole host of problems.

The first is the one federal judge Amit Mehta noted Monday. When Trump lawyer William Consovoy tried to argue that Congress had no such right, Mehta noted that this standard would render illegal the congressional Watergate and Whitewater investigations, which led to the resignation of one president and the impeachment of another.

Mehta asked whether “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?” Consovoy answered in the affirmative, if it was “not pursuant to its legislative agenda.”

So how do you hold a president accountable for illegal actions? The Justice Department has determined that it can’t indict a sitting president. Given that policy, special counsel Robert S. Mueller III decided he couldn’t even accuse Trump of the crime of obstruction of justice. The only remedy for presidential wrongdoing, then, is through impeachment, which is enshrined in the Constitution. According to Consovoy and Cippolone’s logic, though, the Justice Department can only assemble the evidence and Congress can do nothing but decide whether to impeach.

But what happens if the Justice Department, which is under the control of presidential appointees, declines to provide the evidence — either wholesale or piecemeal, as we saw in the Mueller report’s redactions? And what happens if it declines to investigate altogether? Congress would have no means to collect its own evidence to make its constitutionally protected judgment about impeachment.

And finally, the Justice Department itself seems to disagree with this argument — and it said so in the very same memo that exempts a sitting president from indictment.

In a 2000 update to the original 1973 Office of Legal Counsel opinion, a footnote reads (key part in bold):

Moreover, in the event of suspicion of serious wrongdoing by a sitting President, the media and even Congress (through its own investigatory powers) would likely pursue, collect and preserve evidence as well. These multiple mechanisms for securing and preserving evidence could mitigate somewhat the effect of a particular witness’s failed recollection or demise. By contrast, many civil litigants would lack the resources and incentives to pursue and preserve evidence in the same comprehensive manner.

So in arguing that a president is exempted from indictment, the Justice Department pretty much states as a matter of fact that Congress can conduct its own investigation — even stating flatly that it has “investigatory powers.” And the powers it’s describing clearly pertain to presidential wrongdoing, rather than some related legislative purpose.

This, of course, is only an advisory opinion, so it’s legal significance in the looming Trump court battles is up for debate. But it seems pretty telling that the Justice Department saw congressional investigations as a remedy for the lack of an ability to indict and prosecute a sitting president.

Which makes the argument that the Trump team is making all the more remarkable and audacious.