Posse Comitatus Act prevents the military from civil law enforcement. Since the Feds have sued all the states saying that Immigration is a federal issue, if you declare an emergency and a foreign invasion, the military can absolutely be used to enforce immigration laws.
The military cant go about arresting citizens for arson or tax evasion. But i bet aiding and abetting a foreign invasion would hold up....
The military cant go about arresting citizens for arson or tax evasion. But i bet aiding and abetting a foreign invasion would hold up....