It might seem that the nuclear weapons can do everything. Dmitri Trenin has written about the nukes of North Korea that “they both protect the regime from a potential U.S.–ROK attack and allow it to gain international assistance through blackmail…, they also make North Korea look and feel much more important than the impoverished country actually is.” There are thus three main reasons for obtaining nuclear weapons: defense, blackmail, and prestige.
Yet does it work for every case of a nuclear weapons state? Not necessarily. For many such states there is no way to proceed with a nuclear blackmail since this would risk provoking an escalation of conflict and probably a preemptive nuclear strike in the situation of nuclear deterrence, such as the one existing symmetrically between Russia and the United States/NATO, or India and Pakistan, asymmetrically between China and the United States, or China and India, and latently between Russia and China.
Even in the case of North Korea the nuclear weapons are not omnipotent. Can they really defend the country from a potential attack? There is lack of information about the nuclear program of the North Korea to definitely answer this question. According to the assessments of Colonel General (retired) Viktor Esin, former chief of staff of the Russian Strategic Rocket Forces, North Korea may have 6 to 10 implosion-type air gravity bombs with plutonium core. General Esin has written that there is no data to prove “whether North Korea has nuclear reentry vehicles for ballistic missiles.” The development of a high enriched uranium-based warhead would require more tests. The prospects for Koreans to develop an ICBM before 2020 are quite clouded.
The current nuclear program of North Korea would hardly deter a potential first attack, not to speak of ensuring nuclear retaliation which would require North Korea to have survivable nuclear forces capable of avoiding interception by the air and missile defense of the neighbor countries and the United States. The participants of the IMEMO-NTI conference on “Reviving Nonproliferation Regime on the Korean Peninsula” correctly argued that “North Korea regards building up its nuclear and missile potential as a fundamental prerequisite for maintaining the regime and ensuring the country’s security against external pressure, and will therefore make vigorous efforts to develop this potential.” Yet this rather outlines a possible future role for nuclear weapons of North Korea, than describes their actual existing capability.
As for the current situation, the Soviet Union’s experience could be illuminative for North Korea. Despite an efficient and gigantic nuclear arsenal, the former collapsed due to domestic reasons. There is a similar situation in Pakistan, which has “eaten grass” to build nuclear weapons to deter India, but has to deal mainly with dangerous challenges of domestic origin.