Crispin Rovere and Kalman A Robertson suggest eliminating low-yield non-strategic nuclear weapons ^[1] (NSNW) in ‘Non-strategic nuclear weapons: The next step in multilateral arms control ^[2]’. I’m sceptical of their proposed solution—a Minimum Yield Threshold Treaty. Firstly, their definition of a ‘low-yield’ weapon as having a yield of 5 kilotons (kt) or lower is open to challenge given the nature of modern nuclear weapons which have selectable yields. This definition creates a serious problem because states with low-yield NSNWs can design such weapons to have yields higher than 5 kt, and be excluded from any minimum-yield threshold treaty. This would make any such treaty relatively easy to circumvent from a technical standpoint.

A more fundamental problem is how to make such a treaty actually happen. How do you convince North Korea, Israel, India and Pakistan, and potentially Iran in the near future, to sign an agreement to ban low-yield NSNWs? New nuclear weapons states choose to acquire these weapons in line with what they judge to be their strategic interests. For example, Pakistan’s acquisition of NSNWs can be seen to be a response to a combination of Indian conventional military advantage, and lack of Pakistani geographical depth along the lines of any Indian military advance, together with lack of warning time under Indian ‘Cold Start’ military doctrine. Removal of Pakistan’s NSNWs would see Islamabad faced with either a quick defeat at the conventional warfighting level, or rapid escalation to strategic nuclear strikes on Indian cities in the event of a major conflict on the subcontinent. Pakistan’s rapidly growing nuclear arsenal generates a security dilemma for Delhi in return, which responds through its own nuclear modernisation.

The challenge isn’t just for new nuclear weapons states. Whilst President Obama pushes for deeper cuts in strategic nuclear weapons, Russia is resistant to the issue of NSNW being considered in any future multilateral arms control agreement. Moscow has large numbers of NSNW to offset NATO, and more significantly, growing Chinese conventional military advantage in the Far East. Meanwhile China makes it clear that it is not yet ready to consider entering into multilateral approaches on strategic nuclear weapons. At the 2013 Carnegie International Nuclear Policy Conference, Gen Yao Yunzhu stated that ^[3] ‘China sees opacity as an integral part of China’s no first use policy’. In this regard, concerns ^[4] about just what’s in China’s massive underground complexes in Heibei province are justified. The US and its partners simply do not know what they contain. Until the opacity of China’s nuclear forces is transformed to transparency, China’s adherence to a proposed minimum yield threshold treaty would not be verifiable.

The language of ‘nuclear taboo’ and ‘norms’ against nuclear use run throughout the authors’ argument, and reflect a uniquely Western perspective on the role of nuclear weapons in the 21st century. The so-called ‘nuclear taboo’ did not exist during the Cold War. NATO’s MC14-3 Flexible Response doctrine suggested an early resort to tactical nuclear weapons in Central Europe to counter a Warsaw Pact invasion. Yet now with that particular threat gone, Western strategic thinkers have the luxury of debating legal, ethical and moral arguments for a nuclear taboo and abolition.

The authors suggest that ‘a treaty banning low-yield weapons would create a powerful norm against their retention and use, even among states that fail to ratify it.’ The Comprehensive Nuclear Test Ban Treaty (CTBT) is put forward as evidence that this approach will work. But more and more nuclear testing can be done in simulation, so the CTBT example is not convincing. Likewise, the authors mention diplomatic pressure from the UN General Assembly, but do not provide a causal link that shows that this kind of pressure would necessarily lead to compliance. The authors suggest a legal mechanism would deter cheating, yet recent historical experience with Iran and North Korea tends to suggest such mechanisms are inherently weak and ineffective. The point is that the language of ‘nuclear taboo’ and legal norms do not necessarily resonate in other states that face very different strategic challenges, and have different strategic cultures to the US and Europe. It’s important to avoid mirror-imaging in considering the issue of nuclear disarmament, and vital to recognise that other states may not see a nuclear taboo, at least in terms of acquisition and retention, as valid.

There is greater risk that low-yield NSNW will be used than high-yield strategic weapons. There is a risk that any such use could result in rapid escalation into strategic exchanges. There is a strong case here for strengthening nuclear deterrence against first use of low-yield NSNW, by making it clear to states which rely on such weapons that any such use will see rapid escalatory responses that makes first use an unacceptable option. Secondly, investment in Tactical Missile Defence capabilities, as well as non-nuclear prompt-strike systems to minimise the risk that such weapons can be used in a crisis seems appropriate.

Traditional nuclear deterrence, and non-nuclear deterrence by denial should be explored in addition to arms control. Finally, the security issues which drive states to acquire such weapons need to be addressed. Only when a state’s incentive to acquire and maintain low-yield NSNWs are removed, can we open the door to arms control as a way of finally removing them from operational deployment.

Malcolm Davis is Assistant Professor in International Relations and Post-Doctoral Research Fellow in China-Western Relations at Bond University. Image courtesy Wikimedia Commons ^[5]