Who is doing this allocation? Who is going to tell Pyongyang, Beijing or Moscow they can’t launch anymore?
No UN body can command a nuclear sovereign. They ultimately continually consent to oversight.
Why not, though? If any country violates their limit, just issue a concern. If they ignore it, upgrade it to a grave concern. Then they will surely have to obey, I mean, it's grave concern we're talking about, what else they could do?