Donald Trump’s likely last official act as president was one consistent with the expectations he’d set over the preceding four years: granting a pardon to Albert Pirro, the ex-husband of Fox News host Jeanine Pirro.

The decision encapsulated so many facets of Trump’s presidency, from the translation of personal relationships into manifestations of power to his close alliance with his favorite cable network. Although Trump’s other pardons included a paragraph explaining the rationale for the move and the names of those who’d advocated for the action, Albert Pirro’s didn’t. There was no need.

But the pardon also raised an interesting constitutional question. Could a pardon produced in the last hour of a presidency be overturned by that president’s successor?

The answer appears to be no. The full pardon granted to Pirro, who served 11 months in prison for tax evasion and other crimes, will stand.

There are few powers of the presidency that escape the system of checks and balances, but the pardon power — meant itself to act as a check on the judiciary — is one of them. The accountability that comes into play should a president abuse that power, one expert explained in 2018, is the impeachment of the president and the removal of that president from power — not a robust threat against Trump at this point, for several reasons.

And the possibility of revoking a presidential pardon is not clearly established, at least according to experts with who spoke with The Washington Post.

“Delivery is indeed required before it becomes effective,” Brian Kalt, a law professor at Michigan State University, said in an email. “So it’s not rescinding [a pardon] so much as aborting.”

But what “delivery” means is itself vague in an era when a president can communicate with the entire country instantaneously.

“One could argue that by publishing and announcing them, they are ‘delivered’ well enough for these purposes,” Kalt said. “And as long as they are executed properly, there is no requirement that they be delivered by any particular person.”

He noted that the legal cases establishing the bounds of pardons are old enough that they predate modern communications, introducing some uncertainty.

Samuel Morison, a private lawyer who spent 13 years working for the Justice Department’s Office of the Pardon Attorney, broadly concurs.

“I think there’s no argument that Biden could undo these,” he said in a phone call. “I don’t think there’s any question that these are final and complete pardon grants. The operative legal act is the president’s decision, and there’s no dispute that he actually did it. There’s no ambiguity about it.”

Morison raised an important point about what “delivery” meant in terms of the effect of the pardon itself.

“I think it’s completely contrived to say that, well, that could be rescinded because the pardon attorney hadn’t delivered a single piece of paper to the guy,” he said. “What the pardon attorney delivers is not ‘the pardon.’ The pardon is what the president signs. Only the president can grant pardons. It can’t be delegated. It can’t possibly be correct that what the pardon attorney produces is the operative legal act. It’s not.”

So even if Trump, midflight on what would soon no longer be Air Force One, dashed off a one-line pardon for Pirro, that he meant to do so and that he then communicated it publicly was enough.

“It doesn’t have to be in any particular form,” Morison said. “I think he could do it with a Twitter announcement or a video feed or something like that. That’s an evidentiary issue, not whether it’s legally effective.”

As of writing, the Pirro pardon, like most of the 140-plus pardons Trump granted in the last 12 hours of his presidency, wasn’t delineated on the website of the Office of the Pardon Attorney. It may be the case that, in fact, the pardon was simply a high-stakes game of telephone: Trump talks to Pirro, acquiesces to a pardon, tells his communications team to pass it on to the press pool and the pool then updates the world. This is not how pardons have worked in other presidencies, where the pardon attorney controls and vets the process, but that doesn’t mean it doesn’t have legal weight.

Pirro, it’s worth noting, had filed the paperwork to receive clemency through the pardon attorney. But if Trump worked around that process, the Pirro pardon simply manifests another feature of the Trump presidency: a broad disinterest in how things were normally done.