Nathan got his geography wrong. While the American South was a part of the USA, Yugoslavia wasn't and should not have been. If all American leftists subscribed to Nathan's geography -- all countries in the world should come under American jurisdiction -- the history of anti-imperialism here would come to an end.
US/NATO's operation with regard to Yugoslavia can be better understood when seen as following Machiavelli's advice on acquiring and holding onto new territory:
***** In a different province he must also, as has been said, make himself chief and defender of the less powerful neighbors, and scheme to weaken the powerful and look out lest by some accident a foreigner as powerful as himself enter there. And it will always happen that he [any foreign prince who acquires new territory) will be put there by those in it who will be malcontent, either because of too much ambition or because of fear; as was earlier seen when the Aetolians put the Romans into Greece; and in every other province they entered, they were put there by the provincials....He has only to see to it that they [lesser powers and malcontent provincials who welcomed his invasion] not take on too much strength and too much authority; and in order to remain fully the arbiter of that province, he can easily lower those who are powerful with his own forces and with their favor. *****
Yoshie