My take is this situation would fall into a grey area.
A attempted attack took place designed to cause mass casualties. Particularly in the context of the ongoing GWoT, gov’t's first reaction should be this is a part of the larger war.
Posse Comitatus applies to the Federally constituted standing army participating in Law Enforcement in the CONUS.
This grey area exists more because of the current administration insisted on treating terrorism as a LE issue and not a warfare issue. By treating these incidents as law enforcement they move using federal military assets into the realm of Posse Comitatus.
If terrorism was clearly and consistently treated as a warfare issue there would be no question.





