It is interesting to note that North Korea defied the world and joined the nuclear bandwagon the same week that Kanti Bajpai was arguing in Outlook (Fission and No Fizz) that India did not gain anything by going nuclear in 1998. The fact that even a crackpot dictator like King Jong-Il thinks that there is some value in going nuclear should make us re-assess Bajpai's arguments.
The P-5 states—the US, Russia, China, France, and the UK—as well as Israel, India, and Pakistan are not hanging onto their nuclear weapons because of sheer bloody mindedness or because they just want to show off. They perceive nuclear weapons as having a clear strategic value in the current security environment. Nuclear weapons provide an insurance against an uncertain future, and are a clear deterrent against perceived current and emerging nuclear threats to their security. Nuclear weapons have relevance to these actors. In addition, there is an undeniable perception is that nuclear weapons also confer prestige and influence. The international response to India and Pakistan's nuclear development make this very clear. Finally nuclear weapons mean that a state possessing them can never afford to be made to feel desperate. Once a state has nuclear weapons, other states can no longer afford to back it into a corner, or threaten its very existence.
North Korea has acquired nuclear weapons for the same reason that the above states retain theirs—specifically for deterrence against perceived external challenges, regime security, and to exploit the enhanced power and influence that comes with being a nuclear power. In all likelihood, North Korea will be unable to really exploit the 'power and influence' aspect because it lacks all the other essential elements—a functioning and stable economy, an ability to engage meaningfully with the international community, including something worthwhile to offer the international system. But with nuclear weapons, Pyongyang will gain a degree of regime security against perceived external challenges that cannot be ignored. That is the perception of the regime, and certainly no one seems to be in a hurry to use military force against North Korea, given the risks that any retaliation by Pyongyang, as bloody and indiscriminate as it would be at the non-nuclear level, could escalate to a WMD level. This is why it is seriously doubtful that North Korea would ever give up its nuclear capabilities through a process of diplomatic negotiations, now that they have them. Iran is also making the same calculations as its partner in Pyongyang. If there is one lesson regimes like North Korea and Iran would have learnt from the invasion of Iraq, it’s that they should acquire nuclear weapons as soon as possible. The difference in the responses of the US towards North Korea and Iraq is there for all to see.