North Korea is a Communist country and South Korea is propped up by USA as their policy is clear that 'Democracy should be pursued and implemented by any means throughout the world and should be sustained.'With this policy they pursued USSR formore than 70 years incessantly and ultimately succeeded in breaking it up and its brand of Leninism/Stalinism. Same was the scenario in Vietnam. North Vietnam was supported by Communist China for the sake of Communism, and South Vietnam was supported by USA in the name of Democracy. USA was defeated in Vietnam though it succeeded in halting the march of Communism towards south. Even China has ultimately reformed its brand of Communism and has accepted a more Democratic way of polity.
Same will happen to North Korea. North Korea cannot stand upto the might of NATO.