Where is the line between “deference owed to the Executive Branch” and defiance of a court order? That’s a question in the case of a Salvadoran illegal immigrant, Kilmar Armando Abrego Garcia. In March he was deported to a prison in his native land due to an “administrative error,” the Justice Department says. The Supreme Court on Thursday said America must “facilitate” — whatever that means — Mr. Abrego Garcia’s release. 

President Trump is sending mixed signals. He told reporters Friday that “if the Supreme Court said bring somebody back, I would do that. I respect the Supreme Court.” Yet by Saturday Mr. Trump appeared to have changed his tune, in a social media post. It spoke of El Salvador’s president, Nayib Bukele, as having “graciously accepted into his Nation’s custody some of the most violent alien enemies of the World and, in particular, the United States.” 

Mr. Trump added that “these barbarians are now in the sole custody of El Salvador, a proud and sovereign Nation, and their future is up to” Mr. Bukele “and his Government.” Mr. Trump’s remarks echoed a Justice department lawyer’s court filing stating that Mr. Abrego Garcia “is alive and secure” in a Salvadoran prison where “he is detained pursuant to the sovereign, domestic authority of El Salvador.”

On Sunday, Justice added that it viewed the Nine’s ruling as merely an obligation to adjust Mr. Abrego Garcia’s “immigration status to admit him if El Salvador’s government chooses to release him,” Politico reports. The dispute involves “interactions with a foreign sovereign,” Justice said, and courts “cannot compel the Executive Branch to engage in any mandated act of diplomacy or incursion upon the sovereignty of another nation.”

This outcome was foreseen by our A.R. Hoffman in an appraisal of the Supreme Court’s Thursday ruling as “an ambiguous decision that sets the stage for further clashes between the White House and the federal judiciary.” The high court was acting in response to an order from the district court judge, Paula Xinis, that the Trump administration “facilitate and effectuate the return of” Mr. Abrego Garcia “to the United States.” She even imposed a deadline.

That date came and went, though, while Mr. Abrego Garcia cooled his heels at El Salvador’s Terrorism Confinement Center. A few days later the high court issued its unanimous opinion agreeing that Judge Xinis’s order “properly requires” the White House to “facilitate” — but not to “effectuate” — Mr. Abrego Garcia’s “release from custody and to ensure that his case is handled as it would have been had he not been improperly sent to El Salvador.”

To that end, the Nine said the White House “should be prepared to share what it can concerning the steps it has taken and the prospect of further steps.” Yet the high court, too, urged Judge Xinis to show “due regard for the deference owed to the Executive Branch in the conduct of foreign affairs.” Mr. Trump and his Justice Department appear to be construing broadly that notion of deference, if their public statements since Thursday’s high court ruling are a guide.

The Wall Street Journal, in an editorial Friday, reckons that Chief Justice Roberts has been trying “to balance the due process and executive power interests in the case.” The Journal suggests that Judge Xinis “acted as if the Supreme Court had merely offered her counsel she didn’t need to take.” The Journal marks that it’s “in the best interests of the courts and the Trump Administration to avoid a constitutional brawl.”

The one party who hasn’t been heard from on this head is Mr. Bukele. Is the Salvadoran leader prepared to release Mr. Abrego Garcia to the United States or another country? Or is El Salvador holding him for its own good reasons? As luck would have it, Mr. Bukele is due today to visit Washington for a parley with Mr. Trump. It could prove a chance for the two leaders to hash out the question, with all deference due to both nations’ chief executives.