World Police

While discussing the concept of intervention with regards to issues like genocide in class, an argument against the idea was brought up in which the fact that we are not the world police shows that it is not our responsibility to step foot into other countries. While it seems like most poeple feel like genocide is such a terrible thing that something should simply be done to stop it, I have to say that I agree with this argument. The way I see it is that pretty much every country is an idividual system (or a group of systems) that was brought about (mostly) independently of every other country. So all of these systems are set up, trying to impose justice the best way that they can, but none of them function perfectly. Each one has at least a few problems. So it just seems like no matter how morally obligated any of us feel to fix the problems in the other systems, the problems that each system has, combined with inter-system problems, makes it nearly impossible to just fix such problems. (I know this is all really vague, but I don't know anything about genocide or the international community whatsoever, so bear with me.)
Basically I feel like this sort of problem is hopeless because of the fact that each system, built on its own and mostly independently of other systems, simply cannot operate fully and allow for every other system to do the same.
It seems like the best way to really solve all of these problems would be for someone to just get really super powerful and take over the world by force. This would inevitably lead to some terrible world war (or maybe just a giant alliance of countries against this individual one, which could also be a good thing) in which a lot of stuff is destroyed and tons of horrible stuff happens. It sounds bad, but afterwards the whole thing could be in the name of justice, and maybe the world could be just from there on. Imagine it as a sort of reverse-Marxist revolution in which the bourgeoisie finally dominate the proletariat for good. In the name of justice.
Of course this whole thing could just be a lazy copout (ie- God, transcendental realms, etc) in which I wish for some higher authority to make the rules for us because ultimately I can’t agree to anything other than moral relativism and international issues seem too broad and distant to affect me.