Having been in the US military, I honestly think it would be about an even split between people who agree/don't agree but will go along with orders vs disagree/undecided but unwilling to murder civilians.
Of course it would never have been "all or nothing" but I think people would be surprised at where the split is and for what reasons people picked their side.
And I'm being completely serious here: I fully believe members of the US military would carry out a nuclear strike on US soil, as long as it was one of "the woke states", in order to make a point of "oppose us and we will kill all of you even if we die too"
I'll be honest, I don't believe that Israel waited for a "green light" from the US for a second. I don't believe they even bothered to check in the first place.
It doesn't matter because republicans will green light anything Israel wants to do as long as it doesn't hurt their bank account. They gave carte Blanche a long time ago.
All of this is a distraction, from both the US and Israel, for different things. Don't get distracted in trying to point fingers and play the blame game. All players here suck ass for different reasons, with the ones attacking and backing being top of the list.
Nobody asked or gave permission because the answer was always going to be "do whatever you want"