The US military might be battle-hardened and ready for war, but the US public is not. The public is soft and fragile and totally unready for the sacrifices and losses that come from a serious war where we're not an overwhelming force against a tiny Middle Eastern country. The public will not work together collectively to get through a war. We're not going to put up with rationing programs, collecting scrap metal, Victory Gardens, buying war bonds, and take a detour from our careers to work in factories producing ammunition. Hell, half the public couldn't even deal with stay-at-home during COVID and went out protesting when they couldn't eat at the Olive Garden and buy their khakis for a few weeks. Ain't no way we have the intestinal fortitude to put up with a sustained hot war.
There is no military in the world without nuclear weapons that can put enough of a fight to require the US public to collect scrap metal. If the US goes to war with a nation with nuclear weapons, what's left of the whole planet's gonna be collecting scrap metal for the next 200 years.
We acted quickly post-9/11, buying duct tape and trash bags and taking off our belts at the airport.
You may be surprised how the public can be united against a human enemy. The success of the Right during COVID was turning the outrage away from the invisible virus and onto the humans forcing them to wear a mask.
I'll believe it when I see it, hopefuly we never have to. 9/11 was almost 25 years ago--an entire generation. A lot has changed since then. Today, the public is softer, fatter, less healthy, less sane, lonelier, more individualistic and isolated from each other, more addicted to drugs, more addicted to phones, chronically online, narcissistic, and self-obsessed than they were in 2001. And when it comes to playing well with other people they are less tolerant, angrier, more belligerent, less capable of cooperating, defiant against even minor sacrifices that might help others... We have this "in it for ourselves" religion that wasn't as strong in 2001. I don't think even a land invasion by a foreign aggressor could unify us anymore.