From a strategic perspective, the bottom line attraction for states seeking to acquire nuclear ballistic missile submarines (SSBNs) is survivability. States possessing SSBNs cannot be victims of a disarming first strike. They will always possess the ability to strike back with submarine launched ballistic missiles armed with nuclear weapons in order to inflict unacceptable damage on the attacking state. If this logic is correct, bilateral relationships will be stable because neither side will have an incentive to strike first.
Given some of the assertions in this Interpreter exchange on Indo-Pacific regional stability and SSBNs, it is worth revisiting two assumptions necessary to believe in SSBN survivability:
1. That they remain continuously at sea and;
2. They are very difficult to find once deployed.
Both assumptions are largely derived from the way the US and, to a lesser extent, the other powers possessing SSBNs — the British, French and Soviets — theorized about and operated SSBNs during the Cold War.
Yet for a SSBN force to operate continuously at sea requires at least three, but likely even more, of the platforms (depending on possible attrition during actual war) given deployment patterns. Neither India nor China are likely to possess sufficient numbers of SSBNs in the immediate term to operate continuously; in a simple sense, one vessel prepares to go to sea while another deploys and the third refits after its deployment. And of course, both countries must develop the training, tactics and procedures, not to mention maintenance and personnel policies, that would allow for this cycle over time.
There are also reasons to doubt the assumption that SSBNs will be largely undetectable by adversaries in context of the Indo-Pacific. Indian and Chinese submarines, at least for the foreseeable future, are likely to be noisier than Russian, British, and French SSBNs, much less their American counterparts. Moreover, operational and doctrinal features of both navies may ease the inherent difficulties of detecting SSBNs. Both countries have a limited and well-known number of bases capable of housing them. Absent a larger number of hulls, both countries are likely to operate SSBNs in ways detectable to intelligence collection at the strategic and tactical levels.
Indian and Chinese SSBN deployments are likely to spur greater efforts to develop anti-submarine warfare capabilities in many countries in the Indo-Pacific region. With a limited number of platforms, limited ability to spend time at sea, as well as command and control constraints (the importance of which has been raised in Ravi N. Ganesh's post), operational doctrine may derive from a modified version of the bastion concept used by the Soviets in the Cold War. Indian and Chinese SSBNs may remain in port until they 'surge' to pre-designated undersea bastions protected by anti-submarine warfare techniques and surface ships during crises.
Aggressors may thus have incentives to attack adversary SSBNs in their home ports preemptively, as well as to find and neutralize undersea bastions. Unless China or India invests in large scale hardening — think U-boat pens in World War Two adapted to withstand nuclear and deep-penetrating conventional weapons — SSBNs will be vulnerable in their home ports, when transiting to and from those ports and likely, their bastions.
Protecting bastions will be costly: China and India will have to improve their own anti-submarine warfare capabilities as well as devote a large percentage of their existing undersea and surface fleets to defensive measures. There are also opportunity costs; those parts of the fleet devoted to protecting SSBNs will not be available for offensive operations during crises.
Further, if a nuclear state wants to protect against a disarming first strike, there are other potentially less costly ways of doing so. Existing or newly developed missile delivery systems (leaving aside air-launched weapons here) can be either mobile or hardened. Mobility and hardening at the very least introduce uncertainty into an adversary's calculations at, debatably, less cost and while leaving expensive and flexible naval assets available for other missions.
Which brings me back to my original point about naval arms control.
For those interested in strategic stability, not to mention peace, arms control remains attractive. In practical terms, there are remote prospects in the Indo-Pacific of achieving broad based disarmament for the three potential possessors of operational SSBNs, or in the case of Pakistan, diesel electric submarines armed with nuclear tipped cruise missiles. Yet even during the Cold War, the US and the Soviet Union found ways to limit the riskiest forms of military competition. India, China, and Pakistan each possess sophisticated strategic communities well aware of the dangers of nuclear proliferation.
Thinking carefully about arms control measures for SSBNs — one of the most expensive and riskiest forms of proliferation — could begin the path toward to reducing military tensions across the entire region. Third party states like Australia and Japan affected by the nuclear rivalries at sea might provide good offices and perhaps even incentives to initiate arms control negotiations.
Photo courtesy of Flickr user Official U.S. Navy Page.