The US does deserve retaliation from many different countries and people.
However. If the actual homeland were under attack, I think most people would support a war.
Of course there would be some protesting. It depends on why this hypothetical war begins, as far as who would be upset.
The US, to me, is like a family. We fuss, and even fight each other at family gatherings.
But. If someone in the family gets in trouble, we’re all going to jump in.
An actual invasion, wouldn’t be possible. And if it somehow came to that, it would be a MASSIVE strategic blunder to try and walk the country down, house to house.
The more intersection question might be, “what would happen if power grid went down in America?” In that case, we would be our own worst enemies.