Hi curious. I am not a lawyer but my understanding is that a non-military civilian citizen being involved in certain types of hostile action makes them subject to trial by military tribunals. I have not researched it thoroughly...and anyway I am not a lawyer. But collaboration with groups openly hostile to the US puts one under the UCMJ, not the regular state and Federal criminal courts.
As a citizen observer I would suggest that you can find the relevant docs online.
As a anonymous blog participant, I will say that I have read enough on my own to be sure that:
1. Trump's legal basis is all set
2. The targets are guilty
3. There will be military tribunals,
4. There will be a clear split between the crimes handled by the UCMJ versus the regular courts
5.The cases handled under UCMJ will be relatively small
