On Monday, Pakistan announced that it had successfully carried out the first-ever test of its nuclear-capable Babur-3 submarine-launched cruise missile (SLCM) from a submerged platform. The test took place at an unspecified location in the Indian Ocean off the Pakistani coast. Maj. Gen. Asif Ghafoor of Pakistan’s Inter-Services Public Relations released limited footage of the test on Twitter that shows the missile’s ejection, launch, and strike on a target with reasonable accuracy. The Babur-3 SLCM is officially rated for a range of 450 kilometers.
Pakistan’s Babur-3 SLCM is ultimately designed for use with its Agosta 90B diesel-electric submarines, which have reportedly been modified to enable SLCM launches, but remain untested in this regard. Per the Pakistani military’s statement regarding the test, the Babur-3 “is a sea-based variant of Ground Launched Cruise Missile (GLCM) Babur-2, which was successfully tested earlier in December, last year.”
Critically, the Babur-3 is capable of nuclear payload delivery. Once fully developed and tested on-board a submarine, Pakistan would possess – in theory, at least – a sea-based second strike capability. Pakistan has been working toward this capability for years; in 2012, it set up a Naval Strategic Force Command. Pakistan’s statement notes this with little ambiguity: “Babur-3 SLCM in land-attack mode, is capable of delivering various types of payloads and will provide Pakistan with a Credible Second Strike Capability, augmenting deterrence.” Specifically, the statement noted that the Babur-3 test was a “step towards reinforcing [Pakistan’s] policy of credible minimum deterrence.”
Pakistan’s inaugural test of the Babur-3 SLCM raises several questions regarding the future of strategic stability between it and India, as both march toward a nuclear triad. For reference, India tested a 3,000 km submarine-launched ballistic missile (SLBM) variant dubbed K-4 (the naval version of the Agni III missile) from an underwater pontoon in March 2014 before testing it from the Arihant-class submarine last year. Specifically, the consequences of Pakistan acquiring what it perceives as a credible sea-based second strike capability, depending on a range of factors, may both stabilize and destabilize the delicate nuclear balance between South Asia’s two nuclear-armed rivals.
First, regarding a nuclear SLCM capability, the upside is that if Pakistan believes the Babur-3 will enhance the survivability of its second strike forces, it can afford to have a less forward-leaning posture with its land-based tactical nuclear forces. This is primarily because Pakistani military planners will have less reason to fear the “use it or lose it” dilemma at the start of a conflict with India. So if this is a step toward bolstering Pakistan’s belief in the survivability of its strategic forces, that should contribute to strategic stability and may not require its planning to necessarily prepare for the early use of lower-order nuclear options. Pakistan’s possession of the Babur-3 means that it can be more confident overall that any first Indian strike would not be totally disarming.
Nevertheless, there are several problems with the above. First, are Pakistani nuclear submarines actually survivable? The belief that submarine-based nuclear forces are almost completely invulnerable against modern anti-submarine warfare techniques is overstated. The United States’ SSBN force might be, but regional power submarines – such as Pakistan’s Agostas – almost certainly are not. They are noisy and are theoretically more easily detectable than U.S. nuclear submarines. The Pakistani Agosta-class submarines are diesel-electric and so they are quieter than first-generation nuclear submarines, but these boats are far from completely invulnerable. Pakistan possesses just three Agosta 90B submarines, the PNS/M Khalid, the PNS/M Saad, and the PNS/M Hamza. (Pakistan may receive eight modified Chinese S20 Yuan-class diesel-electric submarines that may be capable of fielding the SLCM.)
Like India, Pakistan will have to choose which model to manage its limited nuclear submarines. A ‘bastion’ model that keeps them in port until a crisis makes them extremely vulnerable to being sunk as they are flushed out of known locations. A ‘continuous deterrent patrol’ model runs the risk of unauthorized use and accidents in a crowded Indian Ocean, with possibly limited suitable deterrent patrol boxes, while also giving the Indian Navy ample opportunity to track the signature of the submarines to sink them in war.
Of course, the survivability problem is not one for not only China and India, and certainly Pakistan, but there is increasing evidence that the U.S. was pretty good at tracking even Soviet SSBNs during the Cold War. Whether India can track and kill Agostas remains an unknown, but is theoretically possible. So despite Pakistani perceptions of the Babur-3-equipped Agosta-class submarines contributing to its deterrent, the survivability question may prove destabilizing.
Second, will Pakistan deploy both conventional and nuclear Agostas, and how will adversaries know the difference? Pakistan having its Agosta-class submarines carry missiles tipped with both conventional and nuclear warheads is a recipe for a major catastrophe borne of misperception. In a crisis or war, the Indian Navy will try to sink anything it can find. If Indian ASW forces find a Pakistani Agosta-class submarine, they may have to operate under the assumption that the submarine in question is carrying nuclear SLCMs in addition to conventional warheads. Discrimination, thus, will be a major problem and portends serious accidents and unintended escalation.
Finally, does Pakistan have a sufficient and robust enough command and control infrastructure to safely and reliable manage a submarine based nuclear force? This is another area where the Pakistani Navy faces a problem common to many countries in possession of nuclear submarine forces. How exactly will Pakistan manage a submarine-based nuclear force, where the warhead will have to be pre-mated with the Babur-3 SLCM before the submarine leaves port? Does Pakistan have enough confidence in its very low frequency (VLF) and extremely low frequency (ELF) communication with these Agosta submarines that it can afford to put negative controls on the weapons such that they cannot be fired without central inputs? Probably not.
This leaves us with a dangerous and destabilizing state of affairs where the captain of a Pakistani Navy submarine will likely end up in possession of at least the physical ability to release nuclear weapons when on deterrent patrol. This could lead to serious unauthorized use or accidents. If the submarine captain cannot reach the civilian-led National Command Authority, will he assume it has been destroyed and release nuclear weapons of his own volition? If the answer to this is “yes,” then Pakistan’s sea-based deterrent will be based around a drastically different overarching principle from how it claims to manage its land-based forces, which are kept under central control until deep into a crisis.
Monday’s test of the Babur-3 should encourage analysts in New Delhi and Islamabad to seriously think through some of the above questions. For both India and Pakistan — but especially Pakistan — a question to mull over seriously is whether the command and control (C2) challenges of maintaining a submarine nuclear force are so great and simply generate more vulnerabilities than the deterrence benefits of a questionably survivable platform in a shooting war. Despite the Pakistani military exhortations that the Babur-3 reinforces its doctrine of “credible minimum deterrence,” pushing ahead with an undersea deterrent without full consideration of the associated costs may ultimately prove deleterious to South Asian strategic stability.
Ankit Panda (@nktpnd) is senior editor at The Diplomat. Vipin Narang (@NarangVipin) is an associate professor of political science at the Massachusetts Institute of Technology.