Nuclear weapons have a massive credibility problem. Nowhere is this more visible than a scenario in which a nuclear state tries to compel another state (nuclear or non-nuclear) to change its behaviour. In a book that came earlier this year, Nuclear Weapons and Coercive Diplomacy (Cambridge University Press), Todd S. Sechser and Matthew Fuhrmann elaborate on the problem with nuclear coercion using both theory and empirical data.

The nuclear skepticism theory that the duo develop suggests the following reasons for the failure of nuclear compellence (the authors use coercion in place of compellence throughout the book): a) except for destroying hardened targets, nuclear weapons have little military utility over conventional weapons in achieving the objectives of the coercer, b) the stakes involved in a dispute is usually low for a coercer to credibly threaten the use of nuclear weapons, and c) the cost of using a nuclear weapon for compellence may be very high and may include international sanctions and formation of countervailing alliances. Sechser and Fuhrmann also argue that the idea of enhancing the credibility of nuclear compellence through brinkmanship strategies is vastly overrated. One, leaders are often cautious and do not want to risk escalation in the midst of a crisis. Two, the signals of nuclear brinkmanship moves may either not reach the target or may not be interpreted as the coercer wants it to be.

The nuclear shield argument

Sechser and Fuhrmann have made an impressive case against nuclear compellence. Their argument is, however, a bit weak against the utility of using nuclear weapons as a shield for aggression. In this scenario, the coercer does not issue a threat to the target to alter the status quo, but goes on to proactively change the status quo under the assumption that its nuclear weapons will deter any reversion from the newly forged realities on the ground. Sechser and Fuhrmann list out seven cases (between 1945 and 1995) of military confrontations initiated by nuclear challengers. In only two of these seven, the aggressors were successful. Thus they conclude that nuclear weapons are not very useful even as shields to fortify conventional victories by revisionist powers.

This conclusion should be qualified for three reasons. First, the sample size (of seven cases) is too small to reach any satisfactory conclusion. Second, this line of argument misses other factors that become relevant for ‘aggression behind a nuclear shield’ cases as opposed to normal nuclear compellence cases. For example, it is true that Pakistan failed to extract territory in Kargil (1999) using its military forces but that was because of its conventional inferiority vis-à-vis India. Remember, the promise of nuclear shield works only if the aggressor is first able to change the status quo using its conventional forces.

In a recent piece for War On The Rocks, Vipin Narang and Ankit Panda similarly argue that North Korea will not be able to use nuclear weapons as a shield to occupy South Korean territory because it is faced with “overwhelming conventional and nuclear superiority of South Korea and the United States." In both these cases, the revisionist power (Pakistan and North Korea) is crippled by a conventional power deficit. If the South Korea-US alliance is broken or weakened, North Korea may enjoy a better chance of occupying South Korean territory. The task for North Korea will be easier but will still not be easy by any stretch of imagination—even though it fields a larger army, Pyongyang is far behind Seoul in terms of the quality of weapons and equipment.

An interesting scenario would have emerged if India was a revisionist power. Could it then have been successful in wresting Pakistan-occupied Kashmir using its nuclear capability as a shield?

If a revisionist power—that is, one which has a greater stake in the change of status quo—enjoys conventional parity or superiority against its adversary, its chances of successfully using nuclear weapons as a shield for territorial aggression should increase. Even in the seven cases listed by Sechser and Fuhrmann, only five are where the aggressor enjoyed some form of conventional parity or superiority against its target. The two successful cases are from this subset. Therefore, there is some ground for updating the nuclear skepticism theory for the cases in which states use nuclear weapons as a shield for their military aggression. Factors like conventional balance of power, the stake involved in the revisionist quest of the aggressor, and the alliance systems the aggressor and the target are parts of become important in such cases.

Third, there are also revisionist nuclear powers which enjoy immense conventional advantage over their targets. For example, China has been able to change the status quo in South China Sea because it enjoys immense conventional superiority over other claimant states like the Philippines. The fact that China is a nuclear power is almost redundant here. But not completely. China’s nuclear arsenal will still be a huge factor if a power like the US tries to reverse China’s territorial/maritime gains on behalf of Southeast Asian nations. Sechser and Fuhrmann argue that Iran will not be able to significantly change the status quo just on account of acquisition of nuclear weapons. But again, Iran will just need to use its conventional superiority to alter the status quo in the neighbourhood and other powers like the US, Israel or Saudi Arabia will think many times before trying to reverse the gains of a nuclear Iran. Such a scenario is not unthinkable: just remind yourself of Russia’s annexation of Crimea in 2014. A crisis-centred approach coupled with a quest to narrow down to explicit nuclear compellent threats make Sechser and Fuhrmann miss out on such obvious coercive use cases of nuclear weapons.

South Asia and the sub-conventional angle

Sechser and Fuhrmann fail to look at how Pakistan altered its strategy after the failure of the Kargil adventure. Kargil was essentially Pakistan army re-playing what Narang and Panda call the “Gibraltar playbook". Pakistan had unsuccessfully attempted to wrest the control of Kashmir from India using Operation Gibraltar in 1965. Its nuclear weapons development was also associated with a grand strategy. One of the goals of this grand strategy—as has been outlined by Rajesh Rajagopalan in his Second Strike: Arguments About Nuclear War in South Asia (Penguin Viking 2005)—was to capture Kashmir.

When the “Gibraltar playbook" failed even after the acquisition of nuclear weapons, Pakistan has settled on using sub-conventional warfare against India. The latter has not been able to retaliate adequately using its conventional forces for fear of nuclear weapons coming into play. When the Indian army thought of a Cold Start strategy comprising of quick and limited conventional strikes, the Pakistanis have responded by developing battlefield nuclear weapons and evolving a concept of “full-spectrum deterrence". India has partially dented that concept with its surgical strikes across the line of control in September last year.

Even if Pakistan has failed to implement its grand strategy of using nuclear weapons as a shield to seize Kashmir, it has nevertheless used the sub-conventional option skilfully to frustrate a much larger conventional power in India. India and Pakistan are thus locked in a stalemate where the latter hasn’t been able to use its nuclear weapons to fulfil its grand strategy objectives and the former has not been able to find a lasting solution for Pakistan’s sub-conventional attacks behind the nuclear shield. This sub-conventional angle is completely missing from Sechser’s and Fuhrmann’s book. But since the book doesn’t solely focus on South Asia, it is not too glaring an omission. The book, otherwise, is a creditable addition to works on nuclear compellence.

The author tweets @d_extrovert