We turned up late for WWII?
I'm not necessarily saying I agree with doing it this way, but the U.S. usually has this nasty habit of waiting for somebody to attack us before we kick their arse. I think some are realizing we need to strike first.
But than when we do countries like the UK hate us for our unilaterilism. We might piss the French and Germans off and all of petite, delicate Europa.