The Risks of Pakistan's Sea-Based Nuclear Weapons

Nine days into 2017, Pakistan carried out the first-ever flight test of the Babur-3, its new nuclear-capable submarine-launched cruise missile (SLCM). A variant of the Babur-3 ground-launched cruise missile (GLCM), this SLCM will see Pakistan’s nuclear deterrent head to sea – probably initially aboard its Agosta 90B and Agosta 70 submarines, but eventually, perhaps even on board new Type 041 Yuan-class submarines Pakistan is expected to procure from China.

In a new article in the Fall 2017 issue of the Washington Quarterly, Christopher Clary and I examine some of the novel security challenges Pakistan may experience with its sea-based deterrent. It is already well known that Pakistan has outpaced its primary rival, India, in terms of its nuclear stockpile growth.

On land, low-yield systems, like the Nasr, have also raised concerns of a lower nuclear-use threshold in South Asia. The move to sea can have some positive effects on overall strategic stability; indeed, the perceived survivability of a sea-based deterrent can abate so-called “use-it-or-lose-it” pressures for Pakistan’s land-based forces. But the story doesn’t stop there.

Sea-based weapons can aggravate crisis stability concerns in the India-Pakistan dyad and present unique command-and-control challenges for Pakistan, which may be required to place these weapons at a higher level of readiness during peacetime. Finally, Pakistan’s internal security environment will remain a concern with a submarine-based deterrent. The threat of theft and sabotage may be greater in the case of Pakistan’s sea-based weapons than it is for its land-based forces. In aggregate, we argue that the sea-based deterrent may, on balance, prove detrimental to Pakistan’s security.

Pakistan, like other nuclear states, employs a range of physical and procedural safeguards to ensure that its nuclear weapons are only used in a crisis and a with a valid order from the country’s National Command Authority (NCA). The introduction of a nuclear-capable SLCM aboard its Agosta submarines would necessitate the erosion of some of these safeguards.

For instance, some physical safeguards that Pakistan is known to use for its land-based weapons – including partially dissembled storage, separation of triggers and pits, and de-mated storage – would be impractical at sea. Meanwhile, the experience of other nuclear states, like the United Kingdom, with sea-based deterrents suggests that sea-based nuclear weapons generally see fewer use impediments. Pakistan has long asserted that its nuclear command-and-control is highly centralized, but it remains doubtful that this would remain true for its small nuclear-capable submarine force in wartime or a crisis. The temptation to pre-delegate use authorization may be too great.

Leaving aside the command-and-control and safeguard concerns, sea-based weapons may seriously aggravate crisis stability, in other words, the temptation for India to attack first as a crisis begins. The theory behind a survivable sea-based second-strike capability is more compelling assuming a large submarine force capable of maintaining a continuous at-sea deterrent presence. Pakistan’s submarine force, by contrast, would likely employ a bastion model – meaning that their peacetime locations would be known and hence the submarines would be vulnerable to Indian conventional attack.

Similarly, Indian forces, unable to discriminate whether a detected Pakistani submarine in a crisis was fielding nuclear or conventional capabilities, would have to presume nuclear capability should the Babur-3 see deployment. All of this in turn not only would make Pakistan’s submarine force a prime early-crisis target for Indian forces, but also aggravate use-or-lose pressures for land-based forces.

Ultimately, even if India resisted attacking Pakistani submarines to avoid unintended escalatory pressures, it would at least see value in targeting the Very Low Frequency (VLF) radar facility established at Karachi in November 2016 that would allow Pakistan’s NCA to communicate with its at-sea deterrent in a crisis. This would require some confidence in New Delhi that Pakistan had not pre-delegated use authorization and that Islamabad’s sea-based weapons would still require the transmission of a use-authorization code from the NCA.

Finally, a major cause for concern with Pakistan’s move to the sea with its nuclear forces comes from its ongoing struggle with various radical Islamic militant groups. Here, Pakistan is somewhat unique among nuclear possessor states. While militants have mostly targeted soft targets in urban centers, the Pakistani military has endured major attacks as well. In particular, Pakistan has endured attacks and infiltration attempts at sensitive military and naval sites, some associated with its nuclear program. Then-Defense Minister Khawaja Asif acknowledged that Pakistan Navy insiders even abetted al-Qaeda attackers in the 2014 PNS Zulfiquar attack. (Similar reports surfaced around the time of the 2011 PNS Mehran attacks, too.)

Militants with an eye on Pakistan’s nuclear weapons may find no better targets than sea-based systems with fewer physical safeguards. Moreover, the locations of these weapons would be well-known in peacetime, unlike Pakistan’s land-based weapons. The Pakistan Naval Dockyard in Karachi or the Jinnah Naval Base in Ormara – the two known sites capable of hosting Pakistani submarines – are thus prime for attack, infiltration, and even insider risks. While many of the above risks raised by the Babur-3 are far from unique to Pakistan, no other nuclear state faces a similar level of internal militancy.

The Babur-3‘s introduction presents a classic at-sea deterrent dilemma for Pakistan. It can choose to have its presumed second-strike capability either totally secure or readily usable in wartime. For a range of reasons, Pakistan can be expected to opt for the latter option. This will require real compromises on nuclear weapons security that expose Pakistan’s sea-based deterrent to theft and unauthorized use. Combined with the crisis stability implications and the more mundane concerns rising from costs, a sea-based leg to Pakistan’s nuclear forces appears to be, on balance, a net negative for its overall security.