The U.S military was instantiated in the Constitution. Thought I didn’t have to point that out.
It’s a constitutional conundrum.
Article 1 section 8 US CON:
To provide for calling forth the militia to execute the laws of the union, suppress insurrections and repel invasions;
Then, Posse Comitatus:
18 U.S.C. § 1385. Use of Army and Air Force as posse comitatus
Whoever, except in cases and under circumstances expressly authorized by the Constitution or Act of Congress, willfully uses any part of the Army or the Air Force as a posse comitatus or otherwise to execute the laws shall be fined under this title or imprisoned not more than two years, or both.
Then of course the 2nd amendment:
A well regulated militia being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed.
How do those 3 things interact with each other constitutionally?
It can easily be argued that the framers never intended for a large standing army to exist.
From Article 1 Section 8:
"To raise and support armies, but no appropriation of money to that use shall be for a longer term than two years;"