It's called "ripeness."
I find the whole notion as stated that the Fed gov is now "enjoined" from arresting people as specified in the act ludicrous: if the gov has armed men willing to obey, the judiciary can do nothing.
The real issue which absolutely no one will talk about is why do we have allow entry into our country of all kinds of terrorist supporters, and why can't the gov even discuss Islamic terrorism?
I disagree over the need for “ripeness” in this case, because as part and parcel to this the military detains, not arrests, there is no indictment nor civilian trial, and detainees have little or no right to habeus corpus.
Almost to the very beginnings of the United States, when the US Navy detained foreign pirates, the federal courts still demanded that those pirates be returned to the US for federal trial, not tried and executed by Naval officers on location, which was the common practice by the British Navy.
However, this created a paradox, in giving constitutional rights to foreigners during times of what amounted to war.
During the US Civil War, Lincoln carried out a multitude of unconstitutional acts against US citizens, that only long after the war did congress and the courts address, with mixed results, including the Posse Comitatus Act.
W. Bush decided to approach the situation differently, by using Gitmo, Cuban territory under US lease and control, for foreign prisoners under US military jurisdiction, while keeping any US citizen terrorists in the US courts. A very crafty way to address the problem.
Obama and company, however, have muddied the waters by trying to strip American citizens of their constitutional rights, so as to treat them more like foreigners under the W. Bush policy. This won’t fly, constitutionally.
Congress and the courts cannot negate rights “endowed by the Creator” in the US. While they can suspend them temporarily, this must be adjudicated by the courts. The rights themselves are never lost.
Courts issue declaratory judgments all the time. If one's freedom of action is restricted by an unconstitutional law you can file for declaratory relief.