The salient detail would be a strong distinction of soldiers from police forces. It's only because of the strongly kept distinction that it's notable when federal military personnel are deployed in response to riots, natural disasters, or other national emergencies.
See also the related, but opposite in participant and realm of action, Posse Comitatus Act,
> signed on June 18, 1878 ... limits the powers of the federal government in the use of federal military personnel to enforce domestic policies within the United States.
> updated it in 1956, 1981 and 2021.
I would not have known about its recent updates without this diversion:
> In 2021, the National Defense Authorization Act for Fiscal Year 2022 further expanded the scope of the Act to cover the United States Navy, Marine Corps, and Space Force
But not the Army nor Air National Guards of states, nor the Coast Guard, since law enforcement is part of its mission.
https://en-wp.org/wiki/Posse_Comitatus_Act
The distinction has its own wikipedia page discussing the long history of its relevance, at least 146 years.
https://en-wp.org/wiki/Separation_of_military_and_police_rol...