>interesting that the concept of international law is by definition in conflict of the anarchy of real Realpolitik

not 'by definition'. There's a fairly good case to be made that playing by, and being able to set, international norms is in the long term interest of powerful countries. For one because you don't know when you'll cease to be powerful, which will happen given enough time and secondly because even smaller players can cause significant damage when acting without constraint, a lesson several great powers are currently learning for the umpteenth time.

It's very meathead schoolyard bully coded to think that anarchy benefits you just because you happen to be the biggest dude around. It speaks more to the intellect of current leaders than it does to some fundamental contradiction.

I've updated the language there a bit, but the meaning is the same.

>There's a fairly good case to be made that playing by, and being able to set, international norms is in the long term benefit of powerful countries.

Yes, but it doesn't matter. The entire concept of truly sovereign states existing is the point. The second a state wants to leave the agreement, they just stop cooperating. There is no "greater sovereign" with which you can enforce these rules, and if there is -- say, a bigger country invading a smaller country to enforce the rules -- you're once again in a state of war, and none of the rules mattered in the first place.