One thought might bear a deeper look...

I agree generally with your three post-Crimean things but strongly believe that in the US the threat need not be that credible for most; the ability to hurt us is subject to many vagaries; and -- define 'hurt.'

We don't categorize that easily. I know many that would subscribe totally to your descriptions; I know as many or quite probably more who don't need those things. We're a rather belligerent crew for the most part...

That said, there's no question in my mind that domestic politics drive our wars nor is there any question that the recent ones have seen what you say postulated or used by the whoever was in charge (to one degree or another and even if very flakily for the last few Presidents...). So I agree that's been the method here -- I just do not agree that, for the US, going to war absolutely requires those things.

Bob's world asks a good question:
"Remember when the use of military force by the US was a rare and very big deal?"
His answer is also good -- most American do not remember such a time.

This probably is not a good place for my anti Goldwater-Nichols rant...