I don’t think the States has ever been ready for a real war before it started. Am reading Pogue’s Marshall biography and they certainly weren’t ready before ww ii. I’m not sure any country has been really prepared, as they were organized for the previous war if at all. And nobody is or can be organized for a nuclear exchange.

The States, like other superpowers can do a tremendous amount of damage. If they can survive the initial exchange is another question and I’m not sure any country can make tech weapons in enough quantity. And the States lacks the will to suffer mass casualties in a ww ii style shootout, nor can they easily apply manpower offshore.