The question isn’t whether a federal court can order the Salvadoran government to release Garcia; it can’t.
It’s whether the U.S. government has the ability to secure Garcia’s release. If so, then it can be ordered to do so, because then Garcia is in the “constructive” custody of the United States.
RE: 
Bluesky Social
Anna Bower (@annabower.bsky.social)
It sure looks like they’re going all in on the “the executive branch can ignore court orders if it thinks the court lacks jurisdiction” thing