Here is a stupid thought and it is something i have played with quite a bit.

What if we gave the UN Body stronger powers and more independence from the countries. Allow it to hold it's own army. And make countries into territories like provinces or states of a country. Basically, the same scenario the US has with it's states now occurs between UN and the countries.

Now it is something i kind of disagree but see as a necessary evil if we want to stop majority of the conflicts and stop majority of the extremist and civil wars raging around the world. Also get our worlds shit together for once.