UN

The idea is so common that the UN is some kind of moral authority.  It is strange.

One reason I find people citing is that the UN represents all people in the world, so its decisions are fairer than the decisions of one country. 

There are two problems with this argument.  The first is that the UN does represent people, it represents governments.  Some of those governments may reasonably be thought of as representing the people that live in those countries and some may not.  Some may be little more than prisons.  It comes easily enough to those on the left to speak of Western democracies as not really representing the people but rather some powerful exploiting class.  If we can dismiss the government of the world's oldest democracy's claim to be representative why so readily accept the claim of some third world dictatorship.

The second problem is that the argument is a level of abstraction too high.  It may be true, on average, that the decisions of many countries are more representative of the interests of humankind than the decisions of one but the question we face is not a randomly selected country in multiple iterations of world history played over and over again.  We are talking about this particular world and the decisions of one particular country.  One only has to argue that on average the decisions of the US are more moral than the decisions of the United Nations.  Without getting into whether they are or not, it is not particularly implausible that a particular nation would be over time be more moral on average than the whole.  Indeed, it would be very surprising if it were not the case.  More over the same people who denounce US unilateralism often have in thier own mind a particular nation--one often hears Sweeden or Switzerland--as a moral exemplar.  Implicit in this claim is that that nation is on average more moral than the average. 

Consider this: Britain unilaterally ended the slave trade by force in the early 19th century, well before the US civil war.  If the matter had been put to a vote by the world's governments at the time the decision would have never passed, given that the institution of slavery was still common throughout most of the world outside of Western Europe.  Indeed, the British ended up fight in the Sudan against the Arabs since precisely because the British outlawed slavery.  If there had been a United Nations back then it would never have gone along with ending slavery, let alone the British 'war of choice' to end it.

This brings up a sort of background assumption that a nation powerful enough to act unilaterally is particularly likely to be less moral than average.  This may be the case but there are reasons for expecting the opposite to be the case.  The world's hegemon for the last two centuries has been successively France, Britain and then the US.  Part of the reason that each was the most powerful nation of its time was its morality.  A central reason that each was most powerful in its turn was its capicity as a society to be more moral internally.  France rose to military pre-eminence because of a political system that gave a far greater proportion of its population a stake in the society than any of its competitors.  Britain managed the same trick and later America.  Part of the reason that we remember 19th Century Britain as being so rigidly hierarchical and unfair to the lower classes was the role that Britain had in promoting human equality as an ideal. 

The writings of the British of that period are self-critical of their own inequality.  But compared to any of thier major competitors British society offered much more of a voice in government and opportunity for free expression of opinion and advancement.  A modern society's power is based on its capacity for building large organizations were individuals can cooperate freely.  Therefore, even as the abstract level,  I would not be surprised that we would find it to be generally true that the more powerful society should also, on average (as we statisticians say), to be more moral and fair. 

Why do the combined armies of the Arab countries--populations outnumbering Israel by more than 10 to 1--always go down to humiliating defeat in open warfare?  Isreal is a modern society.  They are able to cooperate and share ideas as well as criticise their leaders (to say the least).  Modern warfare is not a matter of individual courage so much as it is a matter of collective thinking and decision making.  The same Arab societies that cannot form effective modern business corporations (the manufactured goods of the middle East aside from Isreal is less than that of Norway) is likewise unable to form modern armies.  They are unable at the societal level to coordinate activities intellegently.  Internally these societies are ruled by force rather than reason.  That makes them rather nasty places to live (whatever ones views of the Arab/Israeli conflict I refuse to take seriously any Westerner who would claim to prefer living in the former).  But it also makes them weak. 

Rule of the strongest is not a good principle for ruling a society internally.  And yet, paradoxically, it may lead to a fairer world at the level of international society.