LH, you're not dealing with a rationally-led state there. The US had nukes on the Korean peninsula for years (although it was denied) and it did not deter the NK from attacks OR from starting the "Second Korean War" (a/k/a "The DMZ War") or anything else. Not having them there hasn't stopped the DPRK from continuing incursions into the South, nor has it prevented the hijacking of airliners, assasination attempts in South Korea and elsewhere, or much of anything else.

DPRK has a problem, in that during the 60s they sided with China "against" the Soviet Union. This was okay then, but Russia is not the Soviet Union and China is now basically a capitalist society. Unlike 1950, China won't send troops this time and Russia will ignore DPRK. In fact, if DPRK DID nuke someone Pyongyang would find nukes on their doorstep, special delivery from China, Russian, and the US. Fortunately, DPRK military IS reasonably rational....