[doorgunner69]

I suppose the question might be, like the Japanese, do they have the components of a nuke variant on the shelf ready to assemble if needed?

Both countries have the technical expertise and the tactical need if push comes to shove, while having plausible deniability.

[Tallguy]

The conventional wisdom (pardon the pun) is that North Korea does not yet have a warhead small enough to fit on a ballistic missile. They would need another jump in miniaturization to get one small enough to fit onto a smaller diameter SLBM.

The danger here is that the US is using it’s own history as a basis for creating a timeline for how long all this will take to come to fruition. Copycats never take as long as those who originate a given technology.

[GeronL]

South Korean culd probably build a nuke but it will take longer I think, the US probably watches them closely enough where they do not have components on a shelf somewhere.