It sounds good until you explore the details. At the end of the day, someone pays the bills, and whomever controls the checkbook tends to set the agenda. There is no such thing as independence.
Flashback to 1985. The Soviet puppet government was committing all sorts of atrocities against people in Afghanistan. Clearly the moral imperative was to stand up for the "freedom fighters", right?
Right, any human-governed force will be corruptible. Now combine this with another fantasy: A benign Skynet-like central authority for such a force, its prime directive being the maximization of welfare for humans (a utilitarian approach, that has its flaws). Or the authority can be made totally decentralized, i.e. "all people on the world with cellphones vote: should we attack North Korea"?
One problem with this would be the "saving fish from drowning" syndrome, e.g. intervening certain acts where the "victims" are all too willing. An example is France's draconian recent law (which I totally back) against burqas: evidently these women are doing this willingly (http://www.guardian.co.uk/world/2011/apr/10/france-burqa-law...), so how can our force intervene?
The more you think about it, the more you realize that, although the current situation is unacceptable and despicable, there are no clear alternatives to it. This is indeed a sad thought.
>Or the authority can be made totally decentralized, i.e. "all people on the world with cellphones vote: should we attack North Korea"
That's great until you replace "North Korea" with your unpopular region. Asking that same question right now about the US would probably come close to passing.
The western world is founded on the rights of the individual above that of the collective. Your suggestions are counter to this philosophy.
Flashback to 1985. The Soviet puppet government was committing all sorts of atrocities against people in Afghanistan. Clearly the moral imperative was to stand up for the "freedom fighters", right?