The Ultimate Deterrent

It strikes me that North Korea is on a pointless quest for nuclear missiles if their intent is to deter an American invasion or attack.

Even if you discount the lack of an invasion or attack for the last five decades while North Korea lacked nuclear weapons to deter us as proof the Pillsbury Nuke Boy is la-la land loony, North Korea has developed the ultimate deterrent.

In a way, this deterrent is partly a result of their single-minded determination to get nuclear weapons. By spending every cent they got on nukes, missiles, conventional arms, and the usual luxuries for the party loyalists, North Korea has created this:

http://www.globalsecurity.org/military/world/dprk/dprk-dark.htm

Amidst the prosperity of South Korea, Japan, China, and even Russia as indicated by their lights, there lies the black hole of North Korean poverty and failure.

Nobody wants North Korea. Certainly not the South Koreans who'd rather the unpleasant images of North Korea stay in the dark as far as they're concerned. The North Korean leaders can get over themselves. Really. Seoul is just not that into them. And nobody else is pining for them, either.
Who wants that cesspool and the price tag of lighting up their night sky image?

It's the ultimate deterrent. They are truly worthless.