Recently, North Korea conducted a test launch of an intercontinental ballistic missile, the Hwasong-15, that it claimed brings the whole of the United States within its striking range. Weeks earlier, it had conducted what it claimed to be the test of a thermonuclear weapon. With these, North Korea declared itself to be a full-fledged nuclear weapons state, thus ratcheting up the tensions on the Korean peninsula and across East Asia.

If North Korea's claims of its missile and nuclear capabilities are true, they are a big reason for the United States to worry, not only for its own freedom of action vis-à-vis Pyongyang but also for the security of its allies Japan and South Korea. North Korea's missile and nuclear tests have once again started the debate on the proliferation of nuclear weapons. Those who bat for peace have always condemned states that have aspired to become nuclear weapon states. They argue that the threat to the international community rises as the number of states possessing nuclear weapons rises.

Almost two decades back, in 1998, when India conducted five nuclear weapons tests at Pokhran and declared itself a nuclear weapons state, and Pakistan followed  two weeks later  with its six tests, the two countries, too, faced international opprobrium and sanctions.

Critiques argued that a nuclear South Asia would prove to be disastrous and could see the deaths of hundreds of millions in a nuclear exchange. They were proved wrong the very next year when the Kargil conflict did not descend into nuclear war as had been feared. Neither India nor Pakistan brought out their nukes to fight the war. Critiques were right in one thing, though -- that with nuclear weapons, even a small state could deter a much larger state.

India's conventional military strength towered over Pakistan's, until the latter obtained nuclear weapons. This is evident from the results of all the wars they have fought. Once Pakistan obtained nuclear weapons, it deterred India to a large extent from launching an all-out punitive offense after events like the December 2001 Parliament attack and the 26/11 Mumbai attacks in 2008.

Had Pakistan been a non-nuclear weapon state at the time of these events, or even if both India and Pakistan were non-nuclear states, India's response would surely have been very different from what it was. Not that the thought of striking at the adversary with nuclear weapons does not come to mind, with huge public pressure to do so in the backdrop, too, but any responsible state in the international system calculates the outcomes of such an action, especially when the adversary also has nuclear weapons. A Pakistani nuclear hit on India would kill millions, an Indian nuclear retaliation on Pakistan would not just kill millions of Pakistanis but put the country's very survival in doubt. To be sure, India values the lives of its own citizens far more than hitting the enemy state hard; Pakistan values its survival as a state. Which is why, Pakistan seeks to deter India from any military action through a seemingly irrational nuclear first strike doctrine while India does so through a "massive retaliation" doctrine, although in recent months, some people in India have raised questions about the corollary "no first use" policy.

In international relations, it is said that one can never judge the 'intentions' of a state. That is even more true of a state like North Korea, which does not qualify as a responsible state in the international system currently. It must be acknowledged, however, that with North Korea possessing nuclear weapons and the means to deliver them, the US cannot deal with the Kim Jong-un regime as it did with states like Iraq and Afghanistan, which did not have the power of deterrence that comes with the possession of nuclear weapons.

The power of a nuclear weapon state is not in  using  the weapon but in  having  it to deter the adversary. This is because once a state uses such weapons, it risks the wrath of the whole international community at large. Nuclear weapons, therefore, are not weapons for offence but for deterrence. Even their usage for defence can be justified only when a state faces the gravest threat to its security and survival. Otherwise, nuclear weapons cannot be and should not be, used. This was the dictum India lived by after the 2001 Parliament attack and the 2008 Mumbai attack.

Therefore, nuclear weapons make major wars less likely because these weapons have the capability to annihilate a large part of the adversary's, and one's own, population and territory, and its aftereffects are huge. Nuclear weapons in the hands of the Kim Jong-un regime makes a US-North Korea war less likely. But, of course, it all depends on whether North Korea chooses to behave like a responsible state or not.

(The writer is Junior Research Fellow, School of International Studies, JNU).