Excuse me, but who is the judge?

Morgenthau in his article talks about realism and idealism and identifies it as a “great debate”. He proceeds to talk about the difference of what some entity might claim to be versus what it actually is. This argument is then applied to the foreign policies of the United States under the lenses of the realist and idealist points of view. The nation state is described as the unit whose security of interests is justifiable in the international realm. The nation state is then placed in the supranational frame and its interests versus that of the other nations are compared. A framework is also provided for assessing, evaluating and balancing of conflicting interests that might arise amongst the nations. Morgenthau concludes by stating that the competition between that of idealism and realism isn’t that of morality versus immorality but of one type of political morality versus another and providing a test for judging the political and moral content of realism and idealism. The test being which of the two contributes or acts in a manner which safeguards the security and survival of the United States and at the same time ensures and can contribute the most to the security and survival of other nation states. Morgenthau mentions that the competition between the two isn’t of morality or immorality. However, towards the end he presents us with a test which would evaluate its moral and political content. I find it interesting, that Morgenthau considers the fervor with which either of the two would contribute to the interest and security of the United states as the ultimate yard stick. Morgenthau himself says that realism and idealism are different political moralities and their competition isn’t that of morality against immorality. However, towards the end he gives us the set by which the political and moral content could be judged. The point becomes then is it possible to compare moralities? Is there a universal and correct morality? Or is it just the nationalist’s set that becomes the judge?