Self determination unrelated to global obligations
Lack of global political decision-making
Unlimited national sovereignty has spread like a plague across the world since the drafting of the UN Charter in 1945. It was quite natural, but it did not help when the new states emerging from the yoke of colonialism lusted for the same total sovereignty their former masters had. There is no system of decision-making powerful enough to surpass this national drive for supremacy. The result is that international political decisions, even within the United Nations, depend at basis on power manipulation among those nations most able to threaten the others.
Nations, accustomed over the years to being the form in which the world was understood, continue to serve as the primary social unit even when, as today, the primary obligation as human beings is to the entire globe. Thus, refusal by the people of a nation to restrain their right to self-determination blocks the prospect of global unity.