How will the deployment of ballistic missile submarines by China and India affect the Indo-Pacific strategic landscape? What effect will these deployments have on stability in the region? 

Unsurprisingly, the contributions thus far have shown that the picture is, as Rory Medcalf put it, 'murky.' As Bruno Tertrais pointed out, much of the inmpact on stability from these deployments will depend on the quality of the submarines, the range and reliability of their accompanying missiles, and the skill of their crews, as well as on the anti-submarine warfare efforts of their prospective foes. At the same time, as Tom Mahnken noted, a greater sense of second-strike assurance may embolden rather than relax at least China's ambitions. Meanwhile, Rod Lyon has observed that, even with all the qualifiers, strategic submarines tend to make adversary decision-makers think twice about attempting a first strike.

Thus far, the debate seems to be clustering around a general view that the deployment of ballistic missile submarines (SSBNs) is neither a panacea nor a catastrophe for stability, and that much will turn on how they are operated and on how much they are relied on for strategic advantage. 

One aspect of their deployment that has not been sufficiently remarked upon, however, is how the deployment of systems as strategically significant as ballistic missile submarines may influence regional naval doctrine and operating patterns, and even national strategic objectives more broadly. Lyon touched on this point when he wrote that 'even vulnerable SSBNs might have value if deployed in protected bastions, behind layered defensive screens, exploiting known seabed topographies, confusing the targeteer with diversionary noisemakers, and keeping the warhead loadings low per boat.'

The broader point is that effective deployment of a ballistic missile force is not simply about getting a boat into the water with operational missiles loaded.

Rather, attaining more than a bare bones second-strike capability at sea means ensuring those submarines are survivable, can communicate reliably with national leadership, and that their missiles can reach their assigned targets. This is by no means an easy task for a country like China when one faces a highly capable potential adversary like the US Navy, not to mention the Japanese Maritime Self Defense Force, the Royal Australian Navy, and others. 

Accordingly, if China is really serious about achieving an assured second strike capability with its ballistic missiles submarines – by no means an unreasonable supposition, given the cost and scale of the effort – it will need to ensure that these submarines can meet the criteria laid out above. This might be done, as Lyon indicated, by developing sufficiently quiet submarines. We can presume the PLA Navy is working at that assiduously. But will they be sufficiently confident that their submarines are quiet enough to survive, and to survive for long enough? If not, the Chinese may look to other means of protecting their submarines, means that could have considerable strategic consequences. 

Let's look backwards to give some context. As Owen Cote has related, in the 1960s and early 1970s, the Soviet Union deployed its early cruise missile and ballistic missile submarines forward, into the Atlantic. Starting in the mid-1970s, however, the Soviets, alerted to the vulnerability of their submarines by the Walker spy ring, began shifting to a 'bastion' strategy in waters nearer to the USSR, protecting the valuable missile submarines from the US Navy's anti-submarine warfare (ASW) capabilities with layers of defences including air cover, surface ships, and so forth. This entailed a major shift in the doctrine and operating patterns of the Soviet Navy that changed the 'waterprint' of its naval forces. Protecting their boomers, in other words, drove major changes in how the Soviets operated their naval forces, in this case back from forward positions to zones closer to the homeland. 

If China were also concerned about the vulnerability of its missile submarines to the ASW capabilities of the US and its allies, it too might seek 'bastions' and/or other means of protecting these submarines. These efforts at protection could include establishing a higher military presence and even attaining greater control over airspace above the seas in which the PLA Navy would want to operate its submarines. This in turn would mean that Chinese forces might operate and train in seas and airspace that had not traditionally seen much PLA presence and at considerably higher tempos and in a more sophisticated fashion than in the past. China might even seek to obtain formal or informal control or operational dominance over certain seas and airspace – either through gentle means or through coercion – to ensure the security of its missile submarines. 

Such efforts would, of course, have significant political ramifications. But it would hardly be the first time military requirements had helped form political objectives. US requirements for bases during the Cold War drove much of Washington's alliance policy, particularly outside of Europe. And a good bit of Britain's policy in its imperial heyday was motivated by the need for coaling and refitting stations. 

This point should not be carried too far. China is sensitive to political constraints on the exercise of its military power, and we can assume that part of the appeal of SSBNs for Beijing is that they hold out the promise of being able to operate independently and without much fuss. 

Still, in thinking about the implications of China's ballistic missile submarines on stability, we should not ignore that the demands of survivability and operational effectiveness could also entail considerably broader military operational and ultimately political consequences. Much will depend on how much China values these submarines, how quiet it believes them to be, the effectiveness of US and allied ASW efforts, the intensity of rivalry in East Asia, and a range of other factors.

But the point is that the effort to deploy a genuinely survivable and effective ballistic missile submarine force could have consequences well beyond the narrow concerns of submarine quality, crew skill, and missile range.

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 UK Ministry of Defence.