Steve Vladeck is a professor at the University of Texas School of Law, co-editor in chief of Just Security, co-host of the National Security Law Podcast and a CNN legal analyst.

One of the powers that House Democrats will assume when the gavel passes back to Nancy Pelosi on Jan. 3 is the “power of inquiry” over the executive branch — oversight authority that, as the Supreme Court explained in 1927, unquestionably includes the power to compel the production of at least some evidence and testimony from federal officials through subpoenas. As the Congressional Research Service explained in a thorough 2017 report, Congress has an “inherent constitutional prerogative to investigate which has been long recognized by the Supreme Court as extremely broad and encompassing, and which is at its peak when the subject is fraud, abuse, or maladministration within a government department.”

And thanks to rule changes adopted by House Republicans in 2015 (over strenuous objections from Democrats), there is no longer any precedent that subpoenas must receive support from the minority party. Thus, it will surely be only a matter of time before the 116th Congress starts to issue subpoenas to the Trump administration on topics ranging from the president’s finances to the controversial family separation policy at the border to the proposed inclusion of a citizenship question on the 2020 Census to numerous misuses of funds by Cabinet officials — and a whole host of other potential scandals. (The Republicans have already created a helpful list.)

That’s why the next two years have the potential for serious conflict and, perhaps, even a slow-motion constitutional crisis.

It’s quite possible that the Trump administration will defy a subpoena from Congress at some point, and it’s not at all clear what would happen if it did so. There are at least some potentially valid grounds for an executive branch official to decline to comply with a subpoena seeking particular documents, or to answer specific questions if subpoenaed to testify. (For instance, executive privilege protects the confidentiality of certain high-level, internal executive branch communications.) Witnesses also have the Fifth Amendment right against self-incrimination. Other privileges or immunities may also apply depending upon the context. We’ve seen some of these assertions over the past two years, but with very little follow-through from Congress. Now that Democrats control the House, there’s far more incentive for arguments about the separation of powers to be tested. What if there is a dispute over whether a privilege claim is viable?

In such cases, Congress has in recent years increasingly pursued litigation — asking the courts to resolve whether the recipient of the subpoena is legally obliged to comply, on the theory that it will be harder to say no after a court ruling. In one especially noteworthy 2008 district court order, for example, the Democratic-controlled House Judiciary Committee prevailed in a dispute with the Bush administration over whether two former senior White House officials could be compelled to testify as part of an investigation into the resignation of nine U.S. attorneys. (By the time the case made its way to appeal, the Obama administration had taken office, and the question was mooted.) If Trump administration officials invoke privilege claims to defy subpoenas, the courts would be asked to resolve whether those claims are valid.

Such litigation would take some time and could easily end up in the Supreme Court. But while President Trump may think the odds are in his favor at that point, the court has, historically, generally recognized a broad congressional subpoena power — and limited presidential authority to resist otherwise valid subpoenas. In other words, it’s not necessarily a given that even judges and justices appointed by Trump would side with him in such a case.

The question would become whether Trump would back down and order the subpoenaed official to comply, or whether he’d choose to ratchet up the stakes — and dare Congress to formally hold the official in contempt. Nothing would stop the House from voting a contempt citation against an official who refused to comply with a duly issued subpoena.

Enforcing that citation, however, is another matter.

Early in American history, Congress punished contempt itself — exercising an inherent contempt power through which offending witnesses were held in the Old Capitol Jail until they provided the sought-after testimony or the end of that session of Congress, whichever came first. But the Old Capitol Jail is long gone, and Congress’s inherent contempt power has lain dormant ever since. Instead, contempt of Congress today is usually handled through an 1857 federal statute, codified today at 2 U.S.C. § 192, which authorizes Congress to certify a contempt citation to the Justice Department for criminal prosecution. That requires the Justice Department to agree to bring the prosecution, though; Congress cannot force the Justice Department to prosecute anyone for anything. And it’s not hard to imagine a scenario in which this Justice Department would be in no particular hurry to prosecute executive branch officials who, at the president’s insistence, have defied congressional subpoenas — perhaps even after the courts have rejected the grounds on which the subpoenas were defied.

If we get to that point, we could be at a constitutional impasse.

A normal president, especially one running for reelection, would presumably be under significant political pressure even from within his own party to respect the separation of powers and to order compliance with a valid congressional subpoena once the courts had definitively rejected the grounds on which it had been resisted. But this is not a normal president, and whether because or despite Tuesday night’s results, these are increasingly not going to be normal times.