Donald Trump shakes hands with Hillary Clinton at the conclusion of their first presidential debate. (Mike Segar/Reuters)

After the “lock her up” campaign of 2016, President Trump’s administration has an unexpected message for those still investigating Hillary Clinton’s emails: Shut it down.

Trump made clear after the election that he had no appetite to go after Clinton legally, and on Monday his administration went further: His Justice Department went to court to fight those still going after Clinton.

Two conservative legal groups were in federal court in Washington on Monday morning to compel the release of more Clinton emails. And the Trump administration was on the other side.

“It is moot,” said Justice Department lawyer Carol Federighi, telling Judge James E. Boasberg of the administration’s plan to oppose requests for “discovery” by the two legal groups, Judicial Watch and Cause of Action. “Our principal argument is going to be mootness based on all the developments that have happened since the case was filed.”

Federighi was talking about legal mootness: It’s hard to claim that the government hasn’t been forthcoming when 55,000 pages of the former secretary of state’s emails have been made public and the FBI has completed an exhaustive investigation.

(Sarah Parnass/The Washington Post)

But the emails are also politically moot: Clinton lost the presidency, in part because FBI Director James Comey publicly reopened the Clinton email investigation on the eve of the election on what turned out to be dubious grounds. She has returned to private life, and her emails, never revelatory, are now irrelevant.

What’s interesting is that Trump’s DOJ essentially said so — even having Federighi, the same career lawyer who argued the case for the Obama administration, do the same for it.

“It’s incredible,” Tom Fitton, the head of Judicial Watch, told me after Monday’s hearing. “They’re taking the same position as the Obama administration on Clinton.”

Fitton said he suspects the administration sided against him Monday because there aren’t yet enough political appointees at the Justice Department to redirect prosecutors. “I don’t think President Trump would be pleased” with his administration’s defense of Clinton, Fitton said.

That’s one possibility.

Another possibility is the Trump administration will defend executive power like those before it.

A third explanation is the Trump administration finds the whole matter silly and has no wish to encourage legal Captain Ahabs in unending attempts to harpoon Clinton.

Fourteen months ago, Boasberg (whom I’ve known since he was in law school three decades ago) ruled against Judicial Watch, saying that the plaintiffs were on a “hunt for any kernel of fact” even if “marginally relevant.”

But in a surprising ruling released after Christmas, the D.C. Circuit overturned Boasberg’s decision. “Absent a showing that the requested enforcement action could not shake loose a few more emails, the case is not moot,” Judge Stephen Williams wrote. Though previous attempts to get Clinton’s emails released “bore some fruit, the Department has not explained why shaking the tree harder . . . might not bear more still.”

This after the Clinton email tree had already been shaken so much it had dropped not only all its fruit but also its leaves and limbs.

Some conservatives exulted that their vanquished foe had suffered yet another blow. “Trump gets green light to go after Hillary’s emails,” trumpeted WorldNetDaily.com.

But Trump, to the consternation of the Clinton critics, refused to hit the gas. “It’s good to be here during the Trump administration!” a disappointed Fitton told fellow lawyers at the plaintiffs table after arriving for Monday’s hearing.

Boasberg began the hearing by raising his hands in an exaggerated shrug, shaking his head and smiling. “Interesting decision,” he said of the appellate ruling.

Federighi, formerly of the Obama Justice Department and now with the Trump Justice Department, expressed her view that if the request for more Clinton emails wasn’t moot 14 months ago, it certainly is moot now.

“I thought it was clearly moot,” the judge concurred.

James Peterson, arguing for Judicial Watch, declared it “a surprise to us that the new administration continues the position that they don’t need to do anything else” in response to the demands for more Clinton emails.

And John J. Vecchione, representing Cause of Action, attempted the argument that “much of what we know . . . is from press reports, which is not evidence.”

“Not just press reports,” the administration lawyer countered, “but a 17,000-page FBI file.” Federighi expressed her view that “they probably want to range widely over the entire FBI investigation.”

Said Boasberg: “I wouldn’t doubt that for a minute.”

Vecchione argued that he needs to know more — even after an extensive FBI investigation and tens of thousands of emails released, and even though the Trump administration opposes him.

“It’s like peeling an onion,” he said.

Exactly: Once you remove all the layers, you’re left with nothing.

Twitter: @Milbank

Read more from Dana Milbank’s archive, follow him on Twitter or subscribe to his updates on Facebook.