Despite insincere assurances to the contrary, there are two classes of nation-states.

(a) Those who have nukes and sovereignty.

(b) Those who do not.

I'll grant there is a grey zone inhabited by Japan, Taiwan, maybe South Korea where they've had the blueprints for years, and have the components built, but haven't tested and play along at being non-nuclear good citizens.

Everyone else needs a nuclear Daddy, and they need to keep him very happy.