Nuclear weapons at sea in Asia: A tentative concluding assessment

Most discussions about the security of Asia in the 21st century beg the comparison with the East-West confrontation of the 20th. In the nuclear realm, as in other domains, the question 'Is Asia different?' is central. Judgments on the stabilising or destabilising nature of Asian nuclear weapons at sea depend on a few key parameters, on which there does not seem to be major disagreement among contributors to the debate launched in this series:

• It is generally agreed that secure second-strike capabilities at sea were a stabilising factor in the strategic relationship between great powers during the Cold war; there is no a priori reason why things would be radically different for Asia tomorrow.
• Asian nuclear powers already have a modicum of secure second-strike capabilities. Through protection, mobility, concealment and deception, at least some of their land-based missiles are de facto immune to an adversary’s first strike. Or, to put it differently: no Asian nuclear-armed country could reasonably consider that it has a disarming first strike option on another.
• Submarines armed with strategic (ballistic but perhaps also cruise) missiles would thus probably increase strategic stability in the region without necessarily being a complete game-changer.
• However, for that increase in stability to happen, two conditions would have to be met:
• All three major Asian nuclear powers would need to have them; in the meantime, access to strategic submarines by one or two (but not three) could be more destabilising than stabilising.
• Maritime nuclear forces would need to be protected from attack either through continuous at sea deterrence (CASD) or through heavy natural protection (such as the Hainan island base); otherwise, they could become tempting targets, with the risk of adding more instability than stability. This also implies an investment in nuclear force protection (anti-submarine warfare frigates, maritime patrol aircraft etc) to ensure that a ship leaving for patrol does not become an easy target; any investment in a sea-based nuclear capability implies an additional investment in non-nuclear forces.

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• These two conditions are unlikely to be fulfilled anytime soon, and the peculiarities of the Asian maritime theatre (access to oceans, nature of the waters) will make them harder to achieve than in the East-West context. This is another reason why, for operational patrols, 'bastion' practices will be more tempting than 'dilution' ones.
• Because of command and control challenges, countries which combine assertive nuclear control cultures and de-mating practices (China and India) will not naturally be inclined to allow for operational patrols of submarines. In other words, CASD will not come easily to Asia.
• That said, access to modern submarine-based secure second-strike capabilities might be faster, relatively speaking, than it was in the East-West context, due to technological developments that will make some key capabilities (accoustic discretion, secure communications, etc) easier to achieve than was the case in the 20st century.
• It is hard to argue that theatre nuclear weapons at sea (for use against other maritime forces) would increase strategic stability in the region. They may lower the nuclear threshold in a conflict.
• Finally, an inescapable feature of the Asian nuclear landscape is its multilateral nature (four nuclear countries in the region plus Russia and the US). Three independent Asian nuclear actors plan to put part of their nuclear weapons at sea, and since the beginning of this discussion, it has been learned that the fourth (North Korea) may also have plans in this regard. This 'built-in complexity' of the Asian nuclear scene may be more important, at the end of the day, than the structure of the respective arsenals of the countries concerned.

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.

Bruno Tertrais