The US government is run by the people that the american public pick and the various interests try to control.
I think most Americans, those who aren’t pacifists, are in favor of a strong military and not letting “other people” fuck with us. What differs and what the fight is usually about it is “when we should pull the trigger” and when we should “let up”. Politicians, Media, mob psychology help shape the mood of the society.
So US foreign policy doesn’t happen in spite of the American people, but to a large extent with their consent and support….until things start going wrong, then people start “booing the home team” and demanding peace. Remember last election bush got about 49% of the vote, today his poll numbers can’t usually break 20%. those 29% who switched to “bad job” put him there in the first place because they liked the war and fight on terror back then.