The US military spent $4T-$6T in Iraq and Afghanistan, losing ~7k soldiers and ~52k wounded [1]. The US has one of the highest per capita of gun ownership and less than a million soldiers on US soil [2] [3]. Federal supremacy is based on the concept of the US military winning a conflict when they haven't won one since WW2. Force projection via military hardware and popping into Venezuela to extract its leader is a far different proposition than urban combat where your home and family is on the same soil.

I very much hope civil war is unlikely, but the federal government is vastly undermanned if a conflict occurs on US soil.

(have four siblings who have decades in combined military tours across all service branches except the coast guard, and I leverage them as a resource collectively in these matters)

[1] https://www.fcnl.org/updates/2016-10/costs-war-numbers

[2] https://usafacts.org/answers/how-many-troops-are-in-the-us-m...

[3] https://usafacts.org/articles/how-many-people-are-in-the-us-...