Indian nuclear development has been steady but very slow. The recent test launch of the MIRV-capable Agni-5 Inter-Continental Ballistic Missile marked an important milestone. While Multiple Independently Targetable Re-entry Vehicle, or MIRV, technology is not an absolute necessity, it does give India additional options, especially in the face of China’s rapidly expanding nuclear arsenal. But it also raises some concerns.
MIRVing permits a single missile to carry several warheads that can be aimed at multiple targets several hundred kilometres apart. Another advantage is that it enables carrying additional decoy warheads that can help defeat ballistic missile defences (BMDs). This is not an immediate concern because none of the currently operational BMDs can effectively counter ICBM-range missiles. Although the US has deployed its Ground-based Midcourse Defense (GMD) system, its effectiveness against anything more than one or two ICBMs at a time is questionable. Of course, no country is likely to fire just a couple of ICBMs at a time, making its utility suspect. But MIRVing is at least a hedge for the future, should such BMD technologies become available.
Pros and cons of MIRVing
Currently, there is greater utility in adapting MIRV technology to shorter range missiles, such as IRBMs (Intermediate Range Ballistic Missiles). MIRVing can help IRBMs defeat missile defence systems that are designed to counter them, such as China’s S-400s.
Pakistan, for example, has claimed it is developing the Ababeel missile, an IRBM with MIRVed warheads, because of India’s efforts to acquire a BMD system. Ababeel was test fired last October, although it is unclear if it has been deployed. However, the effectiveness of this strategy is questionable. Even though Pakistan’s longest-range missiles are IRBMs, and thus potentially vulnerable to Indian BMD systems, MIRVing them makes no sense. Any Indian BMD is only going to be a point defence system, protecting only the national capital region or a specific target, leaving the rest of the country open to attack. It is typical overkill by Pakistan’s military, though it may be more propaganda than a working system.
MIRVing becomes even more relevant if IRBMs have both nuclear and conventional options since the latter are much more likely to be employed. Several IRBMs are thought to have both nuclear and conventional warhead types, including China’s DF-26 and North Korea’s Hwasong-10, although this has not been officially confirmed by the respective countries.
However, arming IRBMs with conventional warheads presents a couple of problems.
First, should IRBMs be wasted by putting relatively light conventional warheads on them? IRBMs have a potential range advantage because they can attack targets beyond the reach of India’s current combat aircraft, including the Su-30MKI, its heaviest and longest-range combat jet.
But there are at least two disadvantages. One is that putting conventional warheads on IRBMs assumes extremely high accuracy for such missiles. Conventional warheads on ballistic missiles do not pack much of a punch in explosive power, especially if they carry multiple warheads. This means that unless they have pinpoint accuracy, they will not be effective. Even with high accuracy, they are unlikely to be effective against underground or hardened targets. In essence, then, conventional warheads on IRBMs are not a very useful option, especially if they are MIRVed.
The second issue is that using such weapons creates what is known as the “discrimination problem”. This refers to the difficulty defenders face in determining whether the incoming missile is armed with a nuclear or conventional warhead. If the same missile can be armed with both types of warheads, the defender might assume it is a nuclear attack. They may then respond with a nuclear retaliation without waiting to verify the warhead type. Due to the risk of inadvertent nuclear escalation, it is a good practice to not arm the same missile type with both nuclear and conventional warheads. However, this principle is increasingly under challenge as more long-range missiles are armed with conventional warheads.
MIRVing missiles such as Agni-5 is unlikely to cause such confusions because no one, including India, is likely to use ICBMs with a conventional warhead. But there are other issues to consider.
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Strategic quandaries
MIRVing allows for potentially faster expansion of India’s nuclear arsenal. Just 50 additional Agni-5 missiles with four warheads apiece would amount to more than double India’s current nuclear warhead count of 160.
India’s adoption of this technology is a possible response to China’s current rapid nuclear growth. Even though India has not publicly expressed concern, China’s potential pursuit of thousands of nuclear weapons to match the US and Russia could become a serious issue. While New Delhi continues to maintain that nuclear weapons are political tools of deterrence rather than militarily relevant combat weapons, a huge imbalance with China may be difficult to ignore, especially considering India’s “two-front” nuclear threat. Such imbalances and their political effects likely played a role in the Soviet-US arms race in the 1960s and might be driving China’s nuclear expansion today.
In addition, having more warheads on fewer missiles might be more efficient for India. It might be costlier to build missiles, while deploying them in large numbers on land is also difficult given the dearth of suitable land-based deployment options. While China, Russia, and even the US have vast tracts of sparsely populated areas where land-based missiles can be positioned, India lacks this advantage. Fewer but MIRVed missiles could be a solution.
On the downside, fewer missiles with more warheads also means fewer aim points for an adversary to destroy. Hypothetically, if India’s entire arsenal of 160 were to be deployed on four-warhead missiles, it would constitute just 40 aim points for an adversary. In contrast, there would be 160 aim points if India’s warheads were each on single-warheaded missiles. In other words, putting more warheads on individual missiles increases vulnerability.
Finally, India needs to pay much more attention to developing sufficiently long-range submarine-based missiles. Even the new K-4 submarine-launched ballistic missile has a range less than 4,000 kilometres, which means that a good part of China will be outside its range if it is deployed in the southern Bay of Bengal. This capability is a much greater necessity than MIRVing land-based missiles.
The author is a professor of International Politics at Jawaharlal Nehru University (JNU), New Delhi. He tweets @RRajagopalanJNU. Views are personal.
(Edited by Asavari Singh)
