The controversy initiated by allegations of the former Defence Research and Development Organisation (DRDO) scientist, K Santhanam, that India?s nuclear tests conducted in 1998 reached a magnitude of ?only? 25 kilotons instead of the originally claimed 45 kilotons is a good occasion to remind ourselves aboutthe rationale behind the development of nuclear weapons. The actual efficacy of India?s nuclear weapons is indeed something that should be looked into from a technical and scientific perspective. However, I would argue that from a national security perspective, the difference between a 25 kiloton and 45 kiloton warhead is irrelevant.
Nuclear weapons can be deployed as tactical weapons or strategic weapons. If used as tactical weapons, their application can take the form of gravity bombs, bunker-busters, warheads on short range missiles, or even a projectile deployed from a canon. Tactical nuclear weapons would be used on a battle field, against an enemy?s weapons facilities, or other such limited and specific targets. For example, in India?s case, they could be used to target underground Pakistani nuclear facilities that would be hard to destroy with conventional weapons. Their required yield to be effective is much less than 25 kilotons, and is normally less than five kilotons.
The second category of nuclear weapons, those developed for strategic purposes, are the arena where discussions about the upper limit of a weapon?s yield are more applicable. Strategic nuclear weapons are meant to be used on cities and urban population centres, and as such, they can have a very high yield?the biggest one ever tested on the planet was 50 megatons?though most strategic nuclear weapons are much less than that. To put this in perspective, the bomb dropped over Hiroshima was about 15 kilotons, and directly killed about 65,000 people Now, even if India is only capable of a nuclear warhead with a yield of 25 kilotons, if this weapon was to be used over a city like Beijing or Karachi, given population density, the eventual number of fatalities after taking into account the cumulative effects of the fireball, the shockwave, and the radiation fallout, would most probably be higher than the 65,000 people dead in Hiroshima. The destruction would be immense.
Now, the point of having strategic nuclear weapons is not to use them per se, but on the contrary, to convince your enemy not to harm you or your vital interests in any way that would make you use nuclear weapons in retaliation. This goal, known as deterrence, is the cornerstone of nuclear weapons strategy worldwide. India has already proclaimed a ?no first use? nuclear weapons policy, thereby making it clear that it will use its nuclear weapons only if someone uses them against India first. The aim clearly, is to deter any potential adversary from doing so. To achieve this goal, whether India puts 25 kiloton warheads on its missiles or 45 kiloton warheads, does not matter. In the first case, targeting a city like Karachi or Beijing, we would be able to kill more than 65,000 people?if the potential of multiple strikes of this magnitude are not enough to deter an enemy, then a 45 kiloton warhead is not going to do so either. Assuming that our enemy is not suicidal and is unwilling to attack us if we will be able to respond even with 25 kiloton warheads, a key determinant after attaining this yield level becomes the question of a second strike capability.
A second strike capability refers to the ability of a country to retaliate using nuclear weapons after it is struck first by an enemy. So long as a country has at least a triad of delivery systems, with a minimum numerical base, a second strike capability is presumably attained. This serves to convince the enemy that even if they were to attack us first using nuclear weapons, we would have the material capability to absorb the first attack, and then inflict extremely high levels of damage on the enemy in retaliation. India therefore needs to ensure that it has a credible second strike capability by maintaining sufficient and dispersed delivery vehicles for the warheads, including land, sea, and air based platforms.
So far, nuclear deterrence has succeeded worldwide between states that did possess a nuclear weapon, and there is no reason why this will not continue to be the case, even if our relations with China or Pakistan were to sour further. In any debate regarding nuclear weapons, one thing should be clear: nuclear weapons are merely a means to an end; the end goal is optimising national security. Whether India has the capability to deploy 25 kiloton bombs or 45 kiloton bombs, they will have no effect on national security so long as we have a secure second strike capability. If we find ourselves in a position where we actually have to use nuclear weapons as a result of having been targeted first, then the whole purpose of developing such weapons to make us safer has already been lost.
The writer is at Brown University, Rhode Island, US