Fielding a nuclear-tipped cruise missile that can be launched from a submarine will give Pakistan something it has wanted for years—a credible nuclear second strike deterrent. Earlier in the week the Pakistani Navy announced that they successfully test-fired just that for the first. Regardless of if the missile launch was as successful as Pakistan claims it was or not, more tests will follow and it’s likely just a matter of time before the missile becomes operational.
Second strike capability means that even if a full-on surprise nuclear barrage were to knock out a country’s nuclear weapons capability, that country still has the ability to make their attacker pay dearly via a retaliatory nuclear attack. It is considered the pinnacle of nuclear deterrent strategies.
Pakistan’s Babur-3 submarine-launched cruise missile (SLCM) that was tested just weeks ago in the Indian Ocean is an evolution of the land-based Babur-2. The Babur series of cruise missiles were developed partially via reverse engineering US Navy BGM-109 Tomahawk cruise missiles that crashed in Pakistan in 1998. The first and second land-based versions offered just another layer of attack capability for the Pakistani military, but the submarine-launched Babur-3’s strategic significance is far greater. Pakistani military officials claim that the sea-skimming Babur-3 has a 280 miles range and is highly accurate. The missile will likely end up on Pakistan’s three French-designed Agosta 90B class—locally known as the Khalid class—diesel-electric submarines.
These 2,000 ton displacement submarines are quite advanced and are built for open-ocean missions. They can stay submerged for multiple days at a time via their MESMA air independent propulsion (AIP) system. Normal weaponry for the type includes SM39 Exocet anti-ship missiles and 533mm torpedoes.
With the Babur 3’s supposed range of just under 300 miles, and with just three submarines assigned to the task of deploying them (eventually), Pakistan’s fledgling ability to deliver a second strike on an enemy state is quite limited, but it may still be credible. It remains unclear if Pakistan will keep one boat at sea at all times or if they will train to surge-deploy at a moment's notice. Other operational questions remain as well, including what type of command and control interface will be used to authorize a submarine originated nuclear strike.