YL Blog #27: Reinforcing the US Extended Deterrence in the ROK and Japan

February 21, 2020

I attended the US-ROK-Japan Trilateral Strategic Dialogue on September 5-6, 2019 in Maui, Hawaii as a part of Pacific Forum Young Leaders delegation. In this piece, I would like to discuss key lessons of the dialogue session at Maui and lay out next steps for trilateral security cooperation.

Nuclear Policy Discussions among Allies

First of all, participants from the ROK and Japan expressed concerns over the credibility of the US extended deterrence with President Trump’s statements on downplaying the role of alliance. While the working level relationship is robust and alliance coordination mechanism is well in place, there were increasing concerns over the prospect of high-level decision to abort or undermine alliance commitment. As a result, a few participants from the ROK and Japan invoked an example of the US-NATO nuclear sharing to illustrate a way to enhance the US extended deterrence in East Asia.

On the other hand, the US participants expressed subtle opposition against the NATO style nuclear sharing on two grounds. First, the US side urged the ROK and Japanese counterparts to understand better what it takes to have NATO style nuclear sharing, both in operation and burden sharing. The US side questioned whether the ROK and Japan are ready to operationalize and plan nuclear weapons into its respective national security planning, while in mindful of public opinion and potential oppositions. Second, and less explicitly articulated during the discussion, the US participants expressed its concern over escalation control during crisis. The sharing of nuclear weapons, though neither the ROK nor Japan will be able to launch it without consultation with the US in advance, invites uncertainty of controlling escalation from the US side.

Requirements of Coordinated Nuclear Policy

Nevertheless, all three nations agreed in principle that there is a need to enhance allies’ nuclear policy discussions. Such discussion will have to bear in mind the following consequences. First, nuclear policy discussion requires responsibility for all actors, both in operational and financial terms. The US domestic decision making on nuclear sharing notwithstanding, the ROK and Japan should assess the pros and cons of NATO-style nuclear sharing option in terms of its implication on allies’ force structure and costs of such planning. Second, domestic opinion of each nation should be taken into consideration – in particular that of Japan. Co-operating nuclear weapons with the US can invite strong opposition from domestic factions, considering Japanese views on the role of nuclear weapons. Third, broader regional security situation – China and Russia – has to be considered to minimize the potential oppositions from regional actors. While nuclear sharing options may suffice as critical national interest, regional actors may beg to differ and advance its own nuclear posture.

At the same time, North Korea factor should be considered when measuring the pros and cons of nuclear sharing option. In other words, we need to calculate whether the marginal benefit of nuclear sharing option exceeds the negative costs of the DPRK’s enhancement of its nuclear weapons program. It is possible, without full confidence on the US extended deterrence, that the ROK and Japan will develop its own nuclear arsenal or take other measures necessary to compensate for lacking US extended deterrence. Such prevention of nuclear proliferation in the region itself is certainly a benefit. In addition, co-operation of nuclear assets in the region could bolster strong deterrence against adversaries including but not limited to North Korea alone. On the other hand, it has to be noted that the DPRK has expressed critical views on the US-ROK combined military exercises, with or without the US strategic assets such as B-52 bombers. It is certainly the case that the DPRK will respond in its kind on the ROK and Japan’s decision to co-operate the US nuclear weapons in the region.  

Will Coordinated Nuclear Policy Solve Allies’ Concerns? 

Separate, however equally important, issue is that the nuclear sharing option may not address the root cause of allies’ concern on the US extended deterrence. The nuclear sharing option may not address the concern over the credibility of US extended deterrence because such arrangement can be reversed by high-level political decisions, likewise the extended deterrence itself. While such mechanism of co-operating nuclear arsenal in the region offers aesthetic of firm extended deterrence, the fact does not change that the US can change its policy as it withdrew tactical nuclear weapons from the Korean Peninsula in 1990s. Furthermore, the nuclear sharing option does not allow US allies an option to launch nuclear weapons without explicit US consent. In other words, nuclear weapons may be a paper tiger without full US endorsement.

The credibility of extended nuclear deterrence is a puzzle that can never be solved easily. Nuclear policy discussions certainly will have marginal effect on strengthening the US extended deterrence in the region, both in the ROK and Japan. However, such arrangement comes with financial cost and adversaries’ aggressive responsive measures have to be considered. On top of that, a nuclear sharing mechanism may not address the root cause of concern over the credibility of extended deterrence. Considering aforementioned variables, nuclear policy discussions among allies have merits both in terms of minimizing misunderstandings among allies and increasing the credibility of extended deterrence. While it is uncertain how such policy discussion will conclude, the process of nuclear policy coordination will certainly offer a room to address allies’ concern over the US extended deterrence.

Disclaimer: All opinions in this article are solely those of the author and do not represent any organization.