Through a Periscope Darkly: The Nuclear Undersea Competition in Southern Asia Is Just Beginning


Editor’s Note: This is the eleventh installment of “Southern (Dis)Comfort,” a new series from War on the Rocks and the Stimson Center. The series seeks to unpack the dynamics of intensifying competition — military, economic, diplomatic — in Southern Asia, principally between China, India, Pakistan, and the United States. Catch up on the rest of the series

Strategic competition among China, India, and Pakistan has traditionally been land-oriented, with a focus on territorial disputes. On the conventional military front, the Chinese, Indian, and Pakistani navies have received the least attention and resources from their respective governments. Similarly, the development of air- and land-based nuclear weapons has historically taken precedence both in defense budgets and as a means of projecting power. However, as China continues its economic and military expansion across the Indian Ocean, the maritime domain is receiving increased attention, with all three states making a concurrent drive toward acquiring sea-based nuclear weapons.

Traditional deterrence theory posits that sea-based nuclear weapons provide strategic stability by reducing first-strike incentives. Because nuclear weapons deployed aboard submarines at sea are harder to find than weapons stationed on land, they are more likely to survive a decapitating first strike and, therefore, guarantee that the target can retaliate. Assured retaliation means a first strike carries significant risks for the first mover, risks that, in theory, no rational actor would take. For these reasons, nuclear triads are assumed to lead to stable deterrence.

While the emergence of sea-based legs in Southern Asia could be stabilizing in theory, in practice it could erode deterrence stability if China, India, and Pakistan neglect three clusters of challenges: first, developing and exercising operational concepts, second, ensuring survivability, and finally, building robust, redundant command-and-control processes. Navies are expensive to build, man, train, and equip, and there is no substitute for experience operating at sea. The domestic competition for resources between guns and butter and between ground, air, and maritime demands may leave these countries’ navies unable to tackle these challenges effectively. Can China, India, and Pakistan overcome their sclerotic, rigid bureaucracies and entrenched interest groups that have long been focused on land-based military power to navigate these new waters successfully?

Sea-Based Deterrence in Southern Asia

China conducted its first nuclear test in 1964 and began its pursuit of sea-based strategic deterrence in the late 1970s. India and Pakistan crossed the overt nuclear threshold in 1998, and have since made significant strides toward incorporating sea-based platforms into their force postures. The learning curve for these platforms is steep, and as in other countries, the platforms are initially limited by such factors as the ship’s endurance and the sea-based missile’s range and reliability. But there are indications that China has overcome these engineering challenges and India and Pakistan may be on the verge of doing so. China is currently operating four Jin-class ballistic missile submarines that, according to the U.S. Department of Defense’s 2017 China Military Power report, “represent China’s first credible, sea-based nuclear deterrent.” India has extensively tested and (quietly) inducted INS Arihant, the lead in its class of indigenously-developed, nuclear-powered ballistic missile submarines, with INS Aridhaman readying for its sea launch. In January, Pakistan test-fired a Babur-III sea-launched cruise missile from a submerged platform.

It is hardly surprising that China, India, and Pakistan are moving in this direction. While the costs and risks of sea-based nuclear weapons are high, all three states feel acutely, even existentially, threatened by their neighbors (and, in the case of China, by the United States). The Southern Asian neighborhood they inhabit is characterized by growing nuclear arsenals, outstanding border disputes, economic and demographic challenges, increasing reliance on sea-borne trade, and active terrorist and insurgent threats. And unlike in the Cold War, bilateral efforts to address these tensions can only go so far.

Another driver of sea-based deterrence in the region is the strategic chain in which China, India, and Pakistan are locked: Pakistan reacts to India; India reacts to China and, to a lesser extent, Pakistan; and China reacts primarily to the United States. With all four states modernizing their nuclear forces, the chain is having greater ripple effects than in the past when these states generally either lacked the resources to develop sophisticated capabilities or subscribed to minimal deterrence concepts. For instance, China’s longstanding concerns about the survivability of its nuclear deterrent have been exacerbated in recent years due to advances in U.S. counterforce capabilities, including ballistic missile defense and conventional prompt global strike. Similarly, India worries its nuclear arsenal could be vulnerable to Chinese ballistic missiles recently positioned at high altitudes near the Indian border as well as Beijing’s growing investments in space-based assets. Pakistan, for its part, believes India’s twin pursuit of ballistic missile defense and multiple-warhead missiles indicate a damage-limitation strategy — and recent debates over writings by former senior Indian officials have done little to assuage Pakistani fears of a disarming Indian strike. Thus, with survivability concerns paramount, the perceived security benefits of sea-based deterrence appear to be outweighing any costs.

The “Big Three” of Nukes at Sea

China, India, and Pakistan have dedicated significant resources to the engineering challenges associated with putting nuclear weapons to sea, but appear to have paid less attention to the operational aspects. Why is this? First, China and India have long prioritized attaining high-end technologies in the hopes of redressing their imbalance with Western powers. The strategic technical establishments — i.e. those institutions responsible for fissile-material production, nuclear-warhead designs, and nuclear-delivery platforms — have been viewed as guardians of international prestige and, consequently, have wielded considerable budgetary and political clout, even more so than the military services. While Pakistan does not aspire to industrial indigeneity and has a greater congruity between its military and technical establishments, it has often focused on keeping pace with India technologically, with rationales for new delivery systems sometimes coming after the fact. Second, all three countries’ militaries, particularly their strategic elements, are dominated by land forces. Navies operate on a different logic than ground troops, but this fact is often underappreciated by ground warfare-oriented leaders, who lack a nuanced understanding of naval operations and maritime strategy. This dynamic may have led to a belief that operationally, sea-based nuclear weapons are fundamentally the same as the other two legs of the triad.

While the technological advances are indeed impressive, the real difficulty lies in addressing the bureaucratic, financial, and operational hurdles. It is the “big three” non-material elements — operational concepts, survivability, and command and control — that truly determine whether nuclear-armed submarines will result in a credible second strike or an expensive folly.

Operational Concepts

First, nations must design and exercise a concept of operations. Traditionally, states operating sea-based strategic deterrence have adopted either a bastion strategy, with submarines confined to home waters and protected by conventional forces, or continuous deterrent patrols, in which states rely on the inherent difficulty of locating submarines to protect the vessels. States could also opt to keep their submarines in port much of the time, thus reducing wear and tear and extending the ship’s lifespan. However, this model has its drawbacks: Submarines in port are vulnerable, and states must believe they will have sufficient warning to sortie in advance of any threats. Furthermore, the crew is less likely to be proficient in handling the ship and the weapons themselves than if they had been drilling regularly during deterrent patrols.

For India and China, naval nuclear power will give their submarines greater endurance, suggesting that continuous patrols could be an option in the future. However, the small size of their current nuclear-capable fleets and their relative inexperience operating these ships suggests that, in the near term, both India and China would derive the greatest benefit from a bastion strategy. This approach would allow these states to use conventional assets to protect their strategic submarines and deter other states from pursuing them while they gain the necessary experience to operate further afield. The downside of using nuclear-powered submarines is that China and India must plan for long refueling and maintenance periods, during which they may have fewer submarines available for patrols. This will put pressure on both states to increase their fleet sizes to ensure that at least one submarine will always be out of port.

For Pakistan, with its short coastline, few ports, and limited naval assets, the safest place for strategic submarines may be hidden among the noise of the North Arabian Sea. It’s worth noting here that Pakistan’s approach to sea-based strategic deterrence varies from the now-common approach of nuclear-armed ballistic missiles that would be launched from nuclear-powered submarines. Instead, Pakistan has been working to retrofit its Agosta 90B diesel-electric submarines with a nuclear-capable cruise missile, the Babur-III. While diesel-electric submarines are on balance quieter than nuclear-powered submarines, they cannot stay submerged indefinitely and must return to port to refuel regularly, creating vulnerabilities that could be exploited by an adversary. Pakistan thus faces the challenge of operating and protecting strategic submarines in congested waters with relatively few conventional assets that can deter Indian efforts to find and trail these boats. If Pakistan can maintain these ships at sea, however, the noisy waters and unique bathymetrics of the North Arabian Sea could work to its advantage by complicating anti-submarine warfare efforts. This would provide Pakistan’s submarines a degree of protection while at sea without diverting naval or air assets from other missions.


Second, states must prioritize the survivability of the ship and the security of its weapons. Sea-based deterrence depends on whether a state has the capability to strike second, which in turn depends on whether the nuclear arsenal can avoid detection and survive a first strike. There are two ways to improve the survivability of the sea-based leg of the arsenal: increase either the quantity or the quality of the submarine fleet. While China may be able to afford a larger force structure, India and Pakistan will need to make up in quality what they lack in quantity. For states with small fleets, stability ideally requires ships with the endurance to remain submerged at sea for long periods, as submarines in port or on the surface are much more vulnerable. A sense of vulnerability can increase “use-it-or-lose-it” pressures, whereby a state feels compelled to launch its weapons before an adversary can eliminate them, thus undermining stability.

Again, naval nuclear reactors will allow Indian and Chinese submarines to stay submerged longer than a diesel-electric submarine, which must operate near the surface regularly to access atmospheric oxygen and recharge its batteries. Ascending and operating at or near the surface runs the risk of detection and interdiction; the longer a ship can remain submerged, the likelier it is to remain undetected. Pakistan’s challenges are compounded by its limited number of ships and its use of the same types of submarines for both conventional and strategic purposes, making any given ship a potentially lucrative target for strategic anti-submarine warfare efforts. Whether Pakistan’s strategic submarines will also conduct conventional missions is not yet known, but either way, it will likely be nearly impossible for India to determine whether any given submarine it finds is nuclear-armed.

Beyond the survivability of the submarine, the weapons are another potential source of concern. The range of the missiles will in part determine where the ship is likely to operate. Longer ranges mean a ship can operate farther away from a potential target, while shorter ranges mean the submarine has a smaller box in which an adversary is likely to find it on patrol. Weapons security and surety are also critical, both in port and on ship. A comprehensive weapons system stewardship program that addresses both external and insider threats is essential — and expensive. These navies must be prepared to dedicate significant resources to the maintenance, training, and deployment cycle to maintain both the material condition of the platforms as well as the operational proficiency of the crews.

Command and Control

Finally, states must develop robust, redundant nuclear command, control, and communication capabilities, which requires having multiple systems and processes in place. There are two elements of command and control: over the ship itself and over the nuclear weapons aboard the ship. One command-and-control issue China must resolve is whether operational control and asset custody of sea-based platforms will rest with the People’s Liberation Army Rocket Force or the Chinese Navy — or possibly a combination of the two. India has long maintained extremely tight civilian control over its nuclear arsenal, but the deployment of nuclear weapons to sea will require greater trust in the military, particularly the navy. For Pakistan, given its limited assets for relaying commands, communicating orders to its submarines will be a significant hurdle. All states with submarine-based strategic forces generally have one-way communications, since a response from at sea could give away the submarine’s location. In this environment of limited connectivity, states must grapple with the “always/never” dilemma — how to guarantee that launch will always occur when authorized and authenticated by a national command authority while ensuring that an unauthorized launch will never occur.

Additionally, strategic submarines in Southern Asia will likely be carrying weapons that are ready to launch. The risks associated with assembling weapons on board a submarine are greater than the benefits of keeping the warheads de-mated until they are needed. This makes the problem of pre-delegation, or devolving launch authority from civilian leaders to military commanders in the field, even more acute: Some level of pre-delegation is needed for the system to be effective, but it also introduces new opportunities for the misuse of weapons. A combination of technological solutions, such as permissive action links and other locking mechanisms, and operating procedures, such as the two-man rule, could help mitigate the risks associated with nuclear weapons at sea. These challenges must be addressed early and exercised often so states can be confident in their ability to retaliate if necessary.

Bombs on Boats: Projecting the Future

There has been relatively little public discussion within strategic communities in India, China, and Pakistan about these issues, which is worrying in its own right. While some ambiguity is likely necessary, total opacity about sea-based nuclear weapons will leave adversaries to make worst-case assumptions in their own force planning, leading to a costly and dangerous arms race.

These are not one-and-done problems, either. There is an interactive effect between technological advances in anti-submarine warfare and the improvement of strategic submarines — as one state improves its anti-submarine warfare tactics and technologies, its opponent will be forced to alter its routines and upgrade its capabilities to avoid detection and interdiction. China, India, and Pakistan will need to continue investing substantial resources in their submarine programs, as well as in protective forces for these ships, if their sea-based weapons are to remain survivable second-strike capabilities. In the intense intra-bureaucratic competition for resources between these states’ armies and navies, the navies have on balance come out on the losing end. China has made the greatest investments in its submarine program, and seems to recognize the need for continual improvement. India has announced plans to upgrade its submarine force and its navy more broadly. If history is any guide, however, the investments currently in the pipeline will experience significant delays, with new ships delivered late and existing ships extended beyond their planned lifespan. The dominance of the army in Pakistan suggests that the navy will continue to be under-resourced, though the missiles themselves will likely attract continued investment as Pakistan relies ever more heavily on nuclear weapons for its security. In short, the costs of being in the sea-based deterrence business are likely to increase as adversaries hone anti-submarine warfare capabilities — and it remains an open question whether China, India, and Pakistan are prepared to keep pace.

The introduction of sea-based strategic deterrence to Southern Asia represents a significant change in the deterrence equation that has prevailed since India and Pakistan tested nuclear weapons in 1998. The nuclear arms race on the subcontinent and in its environs is nothing new, but sea-based nuclear weapons introduce fundamentally different problems into rigid bureaucracies and navies that have limited capacity to address these challenges on their own. If the emerging sea-based forces remain vulnerable or have ineffective command and control mechanisms, the result may be deterrence instability and a temptation by any one of the three nations to strike first.  Whether all three nations will succeed in deploying a safe, effective, credible, and assured second-strike capability in the form of a nuclear-armed submarine fleet will depend less on whether they can overcome engineering hurdles and more on whether they address the bureaucratic and operational problems that come with sea-based strategic deterrence.


Diana Wueger is a Faculty Associate for Research in the Department of National Security Affairs at the Naval Postgraduate School and a PhD student in Political Science at the University of Chicago. The views expressed are those of the author and do not reflect the views of the Naval Postgraduate School, Department of Defense, or the U.S. Government.

Image: Indian Navy