Nobumasa Akiyama is associate professor at Hitotsubashi University and an adjunct fellow at the Japan Institute of International Affairs.
As Bruno Tertrais writes, deterrence is a psychological process. The ability to pose unbearable damage and the will to use such a capability are not sufficient to constitute the deterrent. Such capability and will must be recognised by adversaries as well as allies which are provided extended deterrence. Thus capability, will and perception are the three essential elements for maintaining the credibility of extended deterrence.
It is true that the formula for a credible extended deterrence has become much more complicated. It is especially true in East Asia. Here I would argue two factors among others.
First, the nature of security threats is changing, and thus the roles of deterrence and extended deterrence have been changing. In East Asia, it is highly unlikely that the US would use nuclear forces to retaliate against a North Korean insurgent attack or a Chinese invasion of small islands under dispute in South and East China Seas, for reasons of proportionality. US nuclear force structure seems to be moving away from the idea of massive retaliation against such small attacks.
Even if the nuclear element of extended deterrence was strengthened, the credibility of extended deterrence would not increase so long as adversaries did not consider nuclear retaliation against relatively small-scale aggression plausible. If potential adversaries perceive that the US would not retaliate with nukes, nuclear deterrence may not work. But it should NOT be considered a failure of US extended 'nuclear' deterrence. Rather, it is typical of the 'stability-instability paradox'. So for strategic stability, and increased security of US allies in the region, it is not sufficient that alliances only strengthen the nuclear part of extended deterrence.
Although the role of nuclear weapons in extended deterrence will not vanish, other elements of deterrence and extended deterrence are increasingly important to maintain credibility by assuring allies and adversaries in various crisis scenarios. Since the role of deterrence is to reduce the risk of conventional aggression as well as nuclear exchange, extended deterrence should pursue the best mix of nuclear, non-nuclear (conventional) forces and political means.
Furthermore, as Shen Dingli points out, there are various interpretations of the effectiveness of extended nuclear deterrence. It indicates that the perception element among three elements of credible extended nuclear deterrence needs to be further considered.
Second, asymmetry between the US and China in force structure and strategic objectives makes it complicated to establish strategic stability in East Asia. While US strategic forces shift towards long-range strategic nukes, the majority of Chinese nuclear forces remain short- and medium-range (although China has been developing its long-range capabilities). US arms control policy values a balance of forces as well as transparency and verification, while China puts more emphasis on confidence building measures such as no-first-use and the negative security assurance, both of which are difficult to verify.
During the Cold War, strategic stability between the US and Russia converged into a balance in the number of strategic nuclear weapons, and was consolidated through arms control treaties by the concept of mutually assured destruction. Two countries developed transparency and verification measures to maintain strategic stability. In such a relationship, the US and Russia admitted that they were both in a mutually vulnerable situation, and mutually confirmed a kind of 'pro forma' standardised strategic stability.
In a time when we are experiencing a paradigm shift regarding the role of nuclear weapons in international security and relationships among nuclear armed states, traditional nuclear deterrence logic that was built upon the history of the US-Soviet (Russian) confrontation does not necessarily guarantee the legitimacy of nuclear weapons or nuclear deterrence. Rather, the necessity of structuring a new logic of 'strategic stability' is rising. There is a need for strategic dialogue to converge different arms control philosophies into a shared vision, involving both nuclear weapons states and their allies.
The Nuclear Reactions column is supported by the Nuclear Security Project of the Nuclear Threat Initiative, as part of a wider partnership between the NSP and the Lowy Institute.
Photo by Flickr user m'sieur rico.
