District Court Judge Karin Immergut’s adroit opinion blocking the administration’s plan to deploy National Guard troops to Portland, Oregon, offers a model for how courts should handle the Trump administration’s many assertions of “emergency power.”

Immergut, a Trump appointee, faced the recurring judicial dilemma of the Trump era: how to deal with a president who lies about the conditions that he claims justify granting him extraordinary power. Trump has been prodigal in invoking “emergencies”—at the border, in cities, even in cyberspace—but nearly all have rested on transparent falsehoods. There has never been an “invasion” of marauding migrants, or a fentanyl “siege,” or a crime wave in Washington sufficient to justify federal deployment. Each supposed emergency has been a pretext for asserting powers Congress never gave him. The pattern is as consistent as it is brazen: declare a crisis, invent the facts to match, and dare the courts to stop him.

The tricky question for the courts—one that supersedes politics and party—is how to evaluate the assertions of such a chronic fabulist when the law presumes a good-faith president. Doctrines of deference—judicial respect for an executive’s factual determinations—make sense when that presumption holds. But with Trump, it clearly doesn’t.

That’s the backdrop for Immergut’s decision. Trump invoked 10 U.S.C. §12406—which allows presidents to call in the National Guard of any state to “repel” an “invasion” or “suppress” a “rebellion”—claiming Portland was “war-ravaged” by “antifa and other domestic terrorists.” He called the city’s residents “professional agitators” and “crazy people” trying to “burn down federal buildings.” Aide Stephen Miller piled on, calling it an “organized terrorist attack” that made military intervention “an absolute necessity.”.....

Trump’s determination, she concluded, failed even that minimal test. The supposed “rebellion” in Portland was no rebellion at all. “Defendants have not proffered any evidence,” she wrote, “that those episodes of violence were part of an organized attempt to overthrow the government.” His claim of emergency was “simply untethered to the facts.”

In straitlaced judicial prose, that’s as close as one can come to calling the president a liar.