The term tactical nuclear weapon (TNW) is used to describe smaller versions of nuclear weapons with relatively low destructive capabilities and an impact radius confined to a limited area as against conventional nuclear warheads which can wipe out an entire city.
Lower-yield versions or miniaturised nuclear weapons can be used to inflict damage on strategic military deployments of the enemy. Hence, TNWs are often referred to as battlefield nuclear weapons or baby nukes. Since the damage is localised or confined to a certain area, the danger of impacting on the civilian population is greatly reduced as compared to a strategic nuclear weapon of the Hiroshima kind.
The TNWs include a broad range of atomic explosive devices like nuclear artillery shells, nuclear landmines and nuclear warheads which can be air-dropped from planes, launched on missiles or fired from artillery guns. The yield of these warheads, measured in terms of kiloton (kt), varies from 0.1 kt to 10-15 kt. A nuclear explosion of a 5-kt yield is estimated to spread total destruction in a little over a one-mile radius.
But nuclear experts warn that though of lower yield, TNWs can be easily misused. Since they are small in size and can be easily transported and stored, they're also susceptible to non-judicious use and even theft by terrorist networks. Not surprisingly, the US administration had panicked at the possibility of Pakistan's nuclear warheads being stolen by Al Qaeda terrorists during the Afghanistan strikes.
Many defence experts hold the view that in the hands of a military regime (like Pakistan), TNWs are far more vulnerable to accidental or unauthorised use than conventional nuclear weapons. Given the fact that they can be deployed on the frontline, they could be fired by commanders in a crisis situation without observing the stringent safety precautions that otherwise govern the launch of strategic nuclear weapons. Furthermore, any misuse of TNWs in civilian areas could potentially lead to a broader nuclear exchange.
So far, only the US and Russia are known to possess TNWs. The US is believed to have about 2,000 of them, of which around 1,700 are supposedly deployed on the mainland and the rest across bases in Europe. The Russians, on the other hand, are suspected to have about 15,000 TNWs including the ones that are deployed, stored or are in the process of being decommissioned. However, the third most prominent player is China, which is suspected to have about 120 TNWs. It is from this stock that some warheads are believed to have been delivered to Pakistan. India does possess strategic nuclear missiles but does not have TNWs.
This perhaps explains Islamabad's nuclear rhetoric. Pakistan is suspected to have 20-30 nuclear warheads but it is not known how many TNWs it has managed to obtain. Significantly, in the past, Pakistani officials have often reiterated that TNWs are part of their nuclear deterrence policy.
Acknowledged international security experts like Eric Arnett have observed that should Pakistan exercise its nuclear option, it might target Indian tank divisions in the Rajasthan desert or iaf bases. These attacks might be perceived as striking at the military since relatively few civilians are likely to be killed.
"Unlike India, the nuclear command and control in Pakistan is in the hands of a few generals. Hence the danger of a strike is more. We have to factor this in while planning our strategy, and not by believing they won't strike," says defence analyst Maj Gen (retd) Afsir Karim.