Mutant
In a perfect world? No. In world where we have eliminated nations and everyone plays fair, of course not.
Should China be allowed to do what it wants? Russia? Like I have been saying all along and history has PROVEN, there will ALWAYS be a country that gets to do what it wants more than others.
In a real world, where every nation is selfish and is looking out for its own interests? If someone has to do it, it might as well be America.
At least with America, you have a separation of powers, have leaders that get swapped out, and is pretty fair when working with its allies. The other 2 nations that are closest to being world cops are dictatorships where you will get ZERO chance of changing government policy if the dictator says no. The other 2 nations in this picture have a dismal record of being even remotely fair to its treatment of its allies, let alone the world. The other 2 nations were both communist and still couldn't get along. It is truly a testament to how incredibly selfish these nations are. The other 2 nations also happen to be ethno states who are clearly ok with overt racism. If they were to run the world, we know how fair these nations would treat their subordinates.
Given all the above and more, America is CLEARLY the best equipped to be world police. While no nation is corruption free, at least our corruption has limits. American politicians have a healthy fear of the press. My leaders have their powers reigned in so if they fail, it won't be a lifetime of failure. My country actually gives a shit, at least to some degree, in regards to considering the interests of our allies. My leaders do not murder their colleagues or black bag their competition in the dead of night. My country doesn't treat females like second class citizens, throw citizens of certain religions into camps (at least RECENTLY, I speak of you Crni), or thinks murdering homosexuals is perfectly fine. My country is not rolling out a social credit system where if your not a good little drone, you will be denied opportunities in life.
Lastly, we may pollute, boss others around, look out for ourselves, but so does EVERYONE ELSE. As long as there are dirty humans eating, drinking, fucking, using power, there will be fighting and killing. There will be competition where there are winners and losers. There will be overpopulation.
We will get to utopia land eventually, but science and technology will get us there, IN TIME. Mean while, we need to understand that the world is a certain way and accept the fact life will not be pretty all the time and everywhere.