The U.S. has them, there is no argument against why any nation capable of manufacturing them shouldn't have the right to defend itself.

Does it have the need to defend itself.
No-one has tried to attack NK since the ceasefire, and no-one has even threatened to.
If anyone did, NK has the ability with conventional weapons to utterly destroy the capital city of SK. That should be a sufficient deterrent.

NK has threatened to attack US and is thought capable of nuclear strikes against West Coast cities and maybe as far inland as Chicago.

You are completely safe in Ireland though Jim.