A Test of Japan's Will Power

In the wake of North Korea's nuclear test earlier today, which caused the UN Security Council to actually issue a condemnation letter, serious questions are bound to be asked of Japan. Specifically, in the wake of these new tests, will Japan be motivated to acquire nuclear weapons?

Several issues are in play here. The first is domestic. Since Japan is the only country to ever be on the receiving end of a nuclear explosion, one could understand why the population has a deep reluctance to proliferate. That being said, the country's leaders have maintained that if and when the US security guarantee can not be trusted, Japan will proliferate. A secret report of the Ministry of Foreign Affairs said in a 1969 memo:

"For the time being, we will maintain the policy of not possessing nuclear
weapons. However, regardless of joining the NPT or not, we will keep the
economic and technical potential for the production of nuclear weapons."

Next, the security environment in East Asia is much different now than it was after World War II. There are several competing powers and several potential trouble spots. China and Taiwan have engaged in sabre-rattling with each other, there is the troubled issue of the Korean Peninsula, and several smaller potential conflicts, such as the dispute between Russia and Japan over the Kuril Islands. With this many potential problems, can Japan afford not to proliferate?

So we've established both that Japan has the economic/technical capacity for nuclear weapons and a sufficient threat environment. But does all that add up to certain proliferation? I'm not sure. The US security guarantee is probably enough to keep Japan from proliferating in the short term, but in the long term, Japan could certainly acquire WMD if the security threats in the region continue to fester. Prime Minister Aso has taken a hardline against North Korea, but whether that means WMD or more money for conventional forces is anybody's guess. One thing is for sure, even though the Japanese population has historical/cultural factors for not like nuclear weapons, if they are facing a grave danger, they will want protection.

For good discussions of this topic, see both Kenneth Waltz's "Structural Realism After the Cold War" and Japan's Nuclear Option: Security, Politics, and Policy in the 21st Century