The Naval War College Review just published an article that discusses the hypothetical conditions that might surround Japan’s acquisition of a nuclear arsenal. “Thinking about the unthinkable: Tokyo’s nuclear option” is an interesting assessment of Japan’s potential path to weaponization.
The authors consider rational and irrational reasoning that might take place within the Japanese government and in the public arena, reasoning which ultimately might culminate in some change to Japan’s long-standing “nuclear allergy.” They highlight the lapses in rational judgment that occur when national security and domestic political agendas intersect. They also emphasize regional instability and a wavering U.S. extended deterrent as key factors.
In my humble opinion, the latter two arguments don’t hold up very well. Yoshihara and Holmes cite the relative decline of the U.S. Navy by more than half since the 1980s and Chinese naval modernization as nascent concerns that could spur the Japanese government to begin a nuclear weapons program.
Though China has embarked on significant modernization, its logistical support for its fleet is still deficient, and certainly inferior to the United States. China faces shortcomings in the size and scope of its Navy and its institutional capacity for effective regulation. Even when operating remotely, and despite a reduction from 600 to 283 ships, the U.S. Navy is far superior to the Chinese Navy.
Even excluding the threat of the U.S. nuclear deterrent, China has far too much to lose from launching an attack on Japan. Since the United States has shown no sign that its commitment to defend Japan has lessened, the underlying balance of power in East Asia remains intact despite Chinese military development.
The authors also sail off course when they consider regional tensions that might be caused by the U.S. intention to engage in gradual, mutual nuclear weapons reductions. Here, they underestimate the value of a good old fashioned Disney villain. North Korea’s recent nuclear tests and historically erratic behavior have brought Russia, China, Japan, and the United States together under the banner of combating a common threat. None of these powers will sacrifice global stability and security on the altar of global zero.
All of the security arguments outlined in the article are important factors to be aware of in terms of the U.S. extended deterrent to Japan. We don’t want to hang one of our closest allies out to dry, and maintaining the credibility of our joint security pact is critical to our relationship.
However, there is no political constituency in Japan with any meaningful public following that supports an independent nuclear deterrent for Japan. Nor is there any doubt in Japan about the relative strength of the U.S. nuclear deterrent vis-à-vis regional threats like North Korea. Japan is a leading voice in favor of nuclear nonproliferation and has come out in support of a START follow-on agreement and Global Zero campaign. Given these realities, Japan’s “nuclear allergy” looks to remain firmly entrenched for the foreseeable future.