One of the points that Daniela makes frequently that I think is important is that the US Army LOST the war in Afghanistan. Traditional militaries find it very difficult to fight insurgencies.
If the fucking very worst happened inside our borders, we are still equipped to defend ourselves. Yes, even against the US Armed Forces.
Insurgents are resourceful, & everyone young & old can join the fight. Insurgencies are decentralized—you can't disrupt a command chain that doesn't exist.