Hardly "one man".
We do not need to trade with these people, not the slightest bit. Taiwan can have nuclear weapons and announce the fact. And the present criminal leadership of North Korea should be destroyed. Then we can talk again about whose ambitions are beyond their capabilities. If they still aren't inclined to be reasonable, they can always try trading with the world through a complete blockade enforced by the US navy.
I believe Taiwan already has nuclear weapons.