Using the US military to guard our National border from incursions by foreign militaries is NOT turning it against "its" people. It is using it to defend the US; which, is its primary mission.
Face them inboard, THEN you are in violation of Posse-Comatatis.
YES!
But given that we have
looong been using the military
IN the USA for spotting hemp fields, that trusty old warhorse,
Posse-Comatatis has already left the gates.
In fact, I think those of you interested in studying the gradual erosion of American's civil liberties and presumption of privacy under the law, might find, upon closer study, that most of the erosion of our right to privacy under the law, was first applied to that scapegoat class (drug users and dealers) to muffle the alarums that might otherwise frighten the general population.
For example, I am informed (but cannot attest to it because I don't have the time or inclination to spend years studying it) that most of the Patriot Act which involves spying on civilians in the USA, is not new intrusions of the right to privacy, but had already been approved ,
willy-nilly, one bad law at a time, so that we can end the scourge of drugs.
We owed to the children, after all, to dismantle those annoying aspects of civil liberties that kept us safe from unwarranted and intrusive spying on us, anyway, I expect.
So how convenient for our legislatures back when they decided that terrorism were everywhere in America, they didn't have to go back over our laws to eradicate that silly notion of the right to privacy.
That had already been taken care of, years ago, much thanks to our never ending war on drugs.