Subject: Judge Rules Trump Cannot Use Alien Enemies Act
...to deport people that are alleged to be members of Tren de Aragua (and likely by extension any other gang, no matter how terrible). The AEA only applies to an organized armed force entering the U.S. and seeking to take over all or part of the nation's territory. That circumstance does not apply to criminal gangs.

Opinion here, I haven't read it in full yet:

https://storage.courtlistener....

Notably, the opinion was issued by a Trump appointee - so that might limit the Administration's standard response of attacking the judge, not the substance of their argument.