Japanese security strategy in the face of China’s rise is indeed a more open book than it once was, though there would seem hardly any evidence yet of Japan’s interest in its own nuclear option (see Hugh White over at Lowy’s Interpreter blog).
The most careful, recent analysis of where Japan stands on the nuclear option comes from Llewelyn Hughes) whose authoritative conclusions on this should be required reading for all those who are becoming agitated about the rapid corrosion of American security undertakings in East Asia and where that might lead Japan.
As Hughes says:
(A) hollowing out of the U.S. deterrent is unlikely to automatically translate into the inclusion of a nuclear deterrent within Japan’s force structure. Nuclear hedging has not been implemented as a coherent national strategy, and sustained political will and organizational cooperation would be required to independently develop a robust nuclear deterrent. The evidence suggests that support for such a policy among domestic organizations cannot be assumed. Japan’s energy bureaucrats, for example, are unlikely to support the transfer of nuclear materials for military purposes, given the repercussions for the civilian nuclear energy program. Evidence also suggests that Japanese military planners believe that the costs of independent nuclearization outweigh any security benefits. Finally, polling shows that public preferences against nuclearization are stable, suggesting that Japanese public opinion is likely to remain a significant constraint on policy change even in the absence of Japan’s bilateral alliance with the United States. [See the whole piece]
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See also:
More on Japan, America and the bomb
Japan assesses the next US presidency
Obama and Asia
What Obama means for Asia
Managing the Japan-US alliance
Keeping up with Asia
Obama and Japan’s security policies
Although I generally agree with Llewelyn’s whole argument, I think that he underestimates the importance of the US extended deterrence for Japan, while overstating the impact of domestic normative constrains. Among various variables he specified, the US-extended deterrence through the US-Japan alliance is definitely the most important factor that has enabled Japan to keep its status as a nonnuclear state. Without alliance relations with the US, it would have been very difficult for Japan to maintain its self-defence posture since the end of the WWII. Furthermore, it is the alliance that has enabled Japan’s domestic normative constrains (such as ‘three non-nuclear principles’) keep unchanged for such a surprisingly long period. This in turn suggests that each factor he suggested—policymakers’ perceptions of costs and benefits, opinion polls, domestic organizations’ support, etc—can easily change if Japan no longer has the security relation with the US (whatever people say now!). Thus, there is no reason to believe that ‘a hollowing out of the U.S. deterrent is unlikely to automatically translate into the inclusion of a nuclear deterrent within Japan’s force structure’.
The future security situation for Japan may not be so clear-cut. Japan is not likely to be faced with the stark choice of rock-solid US extended deterrence versus no security relationship with the United States. It is difficult to imagine a complete rupture of the US-Japan security relationship. Japan is too important to the United States in missile defence and other aspects of the joint military balancing of China. It is possible, however, that Japan might be faced with a gradual weakening of the US commitment to its defence. Depending on the quality of this decline (a pullback of American forces from Japanese bases is one possibility, for example), a polarising political debate might ensue in Japan over whether or not it should pursue the nuclear option. Not only would this be domestically destabilising (1960 revisited?), but even having this debate in Japan would likely have negative security consequences in NE Asia, particularly in Japan’s relations with China and the two Koreas. The most important question that must be asked of Japan’s exercising the nuclear option is: would it increase or undermine Japanese security? The coolheaded strategic analysts in Japan (as opposed to the nationalistic hotheads) have calculated, rightly, that it would erode rather than enhance Japanese security. Perhaps Japan should remain content with its nuclear threshold status, which offers a deterrence of sorts. It should also be remembered that the three non-nuclear principles are not just normative constraints; they are political ones too.
Having now read Nishihara’s article, I think his main argument is that Japan could do a lot more in terms of conventional defence, particularly beefing up its maritime defence capability and deploying a well thought-out defence strategy to deal with the increasing military threat from China to its maritime interests and territories in the NW Pacific. As Nishihara says, the lead-up to the new NDPG provides an opportunity to do this.
I think that the question is very simple. Does Japan have nuclear weapons if the US no longer provides a credible nuclear deterrence to Japan? If one believes that the US keeps providing a sufficient level of nuclear deterrence to Japan, then non-nuclear policy can definitely enhance Japanese security. Yet if one perceives that the credibility of the US nuclear deterrence is severally decreasing (such as a pullback of American forces from Japanese bases), then it would be natural for policymakers in Japan to consider a nuclear option. Of course ‘coolheaded’ strategic analysts prefer the former situation to the latter because having nuclear weapons is too risky, as well as costly, compared with relying its security on someone else. This is why Japanese (and also American) policymakers try to maintain the strong US-Japan alliance by all necessary (and sometimes unnecessary?) means.
I agree that the three-non nuclear principles are very political ones. But no matter whether it is political or not, I can hardly imagine that the principles would continue without the US nuclear umbrella. Of course other security means, such as a credible multilateral institution or a security pact between Japan and China, could mitigate security tension in the region, thereby (hopefully) making Japan’s nuclear armament unnecesarry. Yet these security means are unlikely to realise in the near future. As a result, at least so far, the future of Japan’s ‘non-nuclear’ policy depends on whether the US ‘nuclear deterrence’ remains credible or not.
I guess the next question is: at what point can we say that the US no longer provides a credible nuclear deterrent for Japan? This is a pretty critical because it would seem that a Japanese decision to ‘go nuclear’ might depend on it. In my view, the key criterion would be a termination of the Security Treaty and US defence obligations under that, rather than merely drawing back forces to offshore bases.
On a more positive note, one of the strong incentives for the United States to continue providing extended deterrence for Japan is to prevent Japan’s acquiring nuclear weapon. So perhaps there are two key questions 1) does US extended deterrence remain credible, and 2) does the US want Japan to develop nuclear weapons?
Related to the issue of whether Japan’s possession of nuclear weapons would enhance or undermine its security, one also has to ask a question that is extensively debated in the literature: could Japan ever develop its own credible nuclear deterrent? If the answer is ‘no’, then continuing reliance on the US nuclear umbrella is Japan’s only option.
[…] There are new questions about the appeal of Japan’s developing and independent nuclear deterrent. Like me, CRS remains […]