Since 1998, when India and Pakistan both burst out of the nuclear closet and publicly revealed their formerly recessed nuclear capabilities to the world, scant commentary has been made on the impact that the introduction of sea-based delivery systems would have on the South Asian nuclear equation.

This can be attributed, in part, to the relatively recent nature of naval nuclearisation in South Asia. India launched its first indigenously produced nuclear submarine, the INS Arihant, in 2009, and Pakistan only formalised its ambitions for a functional nuclear triad (via an Inter Services Public press release) in May 2012. However, while public discussions in both countries on complex issues such as nuclear naval strategy still remain somewhat inchoate and have yet to fully mature, India's nuclear submarine program was, in fact, initiated over three decades ago. Furthermore, there are statements by Pakistani leaders and naval commanders referring to the need for Pakistan to acquire a nuclear triad that long precede India's public unveiling of the Arihant.

It is important, first of all, to emphasise that both countries have their own distinct sets of motivations to engage in naval nuclearisation.

All too often outside observers almost mechanically hyphenate the two South Asian nations and reduce the multi-layered complexity of their nuclear interactions to a simple action-reaction dynamic. India, for example, is motivated in part by a desire for prestige and international recognition, but also by a very rational objective to place its nuclear assets at a safer distance from a decapitation strike. This is particularly important in light of China's growing militarisation of the Tibetan plateau and the proliferation of Chinese ballistic-missile silos in strategic high-altitude points along the border. In addition, there are mounting concerns over the reach of Chinese air power, Chinese advances in electronic and cyber warfare, as well as over recent reports that indicate China is developing a navalised variant of its 3000km-range Dong Hai 10 cruise missile.

Pakistan has its own strategic rationale for developing a naval nuclear capability which is at least partly independent of a simple desire to mirror India's advances. But the point that bears most emphasis here is that through its threats to disperse nuclear assets among various components of its fleet, Pakistan can offset India's increasingly overbearing conventional naval advantage in the Indian Ocean. When interviewed, Pakistani commanders mention the precedent set by Israel's alleged decision to place nuclear-tipped cruise missiles aboard conventional submarines and have suggested to me, somewhat provocatively, that Pakistan should follow suit.

Another option, some have argued, would be to station nuclear weaponry aboard surface ships and maritime-patrol aircraft. Not only would this provide the country with greater strategic depth, it would also extend some of the more dysfunctional elements of Indo-Pakistani nuclear interactions from land to sea. By threatening, either directly or indirectly, to employ low-yield nuclear weapons at sea, or against an advancing Indian aircraft carrier strike force, Islamabad can hope to acquire 'escalation dominance' and thus considerably dilute its larger neighbour's coercive naval power, much in the same way that it has managed to dilute India's conventional advantage on land.

In both cases, this has been achieved by a refusal to abide by a No First Use (NFU) policy and, increasingly, through a flirtation with the tactical use of nuclear weapons as warfighting instruments. This has been achieved, in part, through shifting from an earlier generation of enriched uranium nuclear weapons to a newer generation of plutonium weapons, allowing Pakistan to significantly expand its nuclear arsenal (which now appears to have overtaken India's nuclear weapon inventory) and to make progress in the miniaturisation of its nuclear warheads for battlefield use.

To provide a concrete example, most analysts now concur that Pakistan is developing a sea-based version of its Babur missile, a subsonic nuclear-capable missile that bears an uncanny resemblance to the US Tomahawk, albeit with a much shorter range.

The introduction of nuclear weapons will have a major impact on the future of naval warfighting in the Indian Ocean. Fleets caught under a nuclear shadow are compelled to operate under different principles. Most notably, ships must loosen their deployment patterns and adopt more dispersed configurations to better shield themselves from the ripple effects of a nuclear blast. For Pakistani security managers, acquiring nuclear-armed cruise missile submarines could provide an opportunity to skew the existing naval power dynamic, primarily by injecting an even greater degree of uncertainty and ambiguity in India's tactical calculus, but also by preventing the Indian Navy from concentrating the bulk of its power projection platforms in one location.

Such a toxic combination of dual-use platforms and doctrinal opacity could prove highly detrimental for crisis stability. In the event of conflict, there would be no way for India to ascertain whether Pakistani vessels or maritime patrol aircraft are nuclear-armed or not, and a radioactive 'fog of war' would float over combat operations.

A common reading of the movement towards sea-based deterrence is that it provides a greater vector for strategic stability, not only by ensuring the relative sanctuarisation of nation's deterrents and thus reducing first-strike incentives on both sides, but also by displacing the locus of nuclear competition from heavily populated state territories to the wide open waters. This optimistic vision does not hold up to scrutiny, however, when applied to regional nuclear dynamics in the Second Nuclear Age. Indeed, in this particular case, one could argue that it is not so much the process of naval nuclearisation itself which is inherently stabilising or destabilising, but rather the manner in which it is being pursued. Pakistan seems to be taking a dangerous path which combines dual-use systems (nuclear-tipped cruise missiles), cultivated doctrinal ambiguity, and a fair degree of maritime brinkmanship.

There are, no doubt, numerous lessons that could be drawn from the Cold War, whose study unfortunately tends to be neglected or oversimplified in South Asia. During the second half of the Cold War, in particular, theorists warned that within a heavily nuclearised environment, and under conditions of strategic uncertainty, offensive submarine operations or deployments could give birth to dangerously escalatory dynamics. And interestingly, much as in contemporary Pakistan, this argument was countered at the time by a constituency that argued that the diversification — and resulting dispersal — of nuclear assets at sea both strengthened their survivability and buttressed overall deterrence.

For instance, Linton Brooks, who served on the Reagan Administration's National Security Staff, wrote in 1986 that:

Deterrence is enhanced through the deliberate importation of both risk and uncertainty...Sea-based systems, able to attack a wide spectrum of targets from a large number of platforms, over a broad spectrum of attack azimuths, complicate Soviet defense planning immeasurably, thus strengthening deterrence.

Depressingly, however, things may in fact be even more complex and unstable now, in large part because the South Asian maritime environment is so alarmingly unstructured. At least during the second half of the Cold War (from 1972 onwards) the Soviets and Americans enacted the INCSEA, which worked towards limiting critical misinterpretations in times of tension. India and Pakistan have no such regime in place, and Pakistan continues to rely on a policy of maritime brinkmanship to compensate for its conventional inferiority.

There are frequent reports, for instance, of near collisions between Pakistani and Indian surface vessels. And in 1999, a Pakistani maritime patrol aircraft was shot down by an Indian Mig-21 when it strayed into Indian airspace. If Pakistani frigates or maritime patrol aircraft were transporting nuclear weapons and such incidents were to reoccur, the implications could be severe.

The scattering of nuclear assets at sea, particularly aboard surface ships, also heightens the risks of a nuclear weapon being intercepted by a malevolent non-state actor, a perennial concern when discussing Pakistan's growing nuclear arsenal. Another question worth raising is whether the escalation dynamics of nuclear warfare in the maritime theatre are less constrained than those that would attend similar operations on land.

A classic example is the tense situation which unfolded underwater during the Cuban Missile Crisis and which almost led to disaster. We now know that each of the Soviet submarines deployed off Cuba was in fact armed with nuclear-tipped torpedoes, a fact which was not known by the US Navy at the time. In an attempt to force the Soviet submarines to surface, the US fleet dropped depth charges which were not intended to hit the submarines but rather to coerce them into revealing themselves. The Soviet submarine commanders, however, viewed these actions under a different light, and one harried commander even ordered his men to assemble the nuclear torpedo to battle-readiness.

This incident highlights two disturbing dimensions of naval nuclear interactions: the perennial risks linked to misperception and ill-conceived or designed signaling, and the various challenges linked to command and control. When it comes to contemporary South Asia, even though Pakistan has threatened to use tactical nuclear weapons against advancing Indian tank formations on land, one could be forgiven for expressing severe reservations over whether Pakistani commanders would be willing to detonate nuclear weapons on their own soil. Out on the open waters, however, such a question remains uncomfortably open.

Finally, analysts will now need to pay much closer attention to the interaction between conventional and nuclear assets at sea, and how this will impact on each country's strategies, doctrines, and acquisitions. Technology, like geography, can blur the line between defence and offense. For example, whereas previously the question of submarine proliferation in South Asia could be viewed through a purely conventional prism, everything will become a lot more complicated now that nuclear-armed and nuclear-powered assets have been thrown into the mix. Formerly conventional naval warfare capabilities such as anti-ship warfare or anti-submarine warfare can now also be equated with counterforce capabilities, with all the destabilising ramifications such a conceptual shift implies.

The Lowy Institute gratefully acknowledges support from the John D and Catherine T MacArthur Foundation for this Interpreter debate, which is part of a broader research, dialogue and outreach project on strategic stability in Indo-Pacific Asia.

Photo by Flickr user Kashif Mardani.