It's worse. The Posse Comitatus act, (
Posse Comitatus Act - Wikipedia) It's not a court case, btw (in fact, the first military action of the United States
under the Constitution was putting down a tax revolt, a
police action, the PC Act was due to Reconstruction, and the dislike of using the military as a rule to police/govern American citizens, as well as the Army used during the Civil war and a bit later in the North to act as police), is in primus: "No, you can't call out the Army to enforce the laws, for every little thing. You
must declare martial law, a clear reason why, and it is a temporary action." Case example is the LA Riots of 1992, once the NG couldn't control the situation, the Marines and the Army (7th ID) swarmed in, shut it down, a week later were gone.
All the services (even though as noted, the Navy and Marines are
not formally bound by the PC Act) do basically however abide by the Insurrection Act's limitations, there are a few exceptions (note the Enforcement acts, which were used to enforce Brown v. Education, with the Airborne) This has a nifty flowchart to show you how it works:
en.wikipedia.org
(the Coast Guard, the Space Force are also
explicitly law enforcement agenices, on top of, or under their primary mission (CG is primarly law enforcement/customs enforcement, SF is primarily military)
PRT... yeah, no. Let's just say this, Wildbow's writing... has shall we say
issues.
Edit reason: Removed a comment not suited for thread.