There is a significant degree of might makes right here. But you know, the world opinion is that it wants a world police man, just not a world bully. Important but sometimes its a small distinction. And the U.S. has been a bully (Afghanistan, Iraq, Vietnam) so there's trust loss on whether the next instance is generally for the benefit of Americans and the world, or only Americans and only in a superficial way?

I mean come on, U.S. decries chemical weapons use in Syria, the official spokesperson makes a Godwin statement about how even a certain bad guy in history didn't drop them out of airplanes on civilian population, and yet umm hello?? Napalm?? Courtesy of Dow Chemical company...

And as for bad things going on in the world, it's approximately a genocide (that it's in the not so gray area, means we've hit the "never again" line in my view) what's going on in Yemen. We looked the other way from genocides in Sudan, and Congo, and Timor. Only so many resources for things like that when there are only so many resources available to recoup the cost. That's the reality.

It's to a great degree U.S.A. Inc. and about the best you can hope for is to not repeat the vicious events of the past. The last Korean war, where no one was really ready for it, wanted it (except Kim), and weren't fighting with today's Weapons Inc. let alone nukes, yet it still got more than a million people killed.

So yes there's a lot about the U.S. to be irritated at, but the world is complex and you have to judge each case.