The following review is by Don Oberdorfer, a fellow at the John Hopkins School of Advanced International Studies.
Mort Halperin has sought to think through U.S. nuclear weapons policy as it affects Japan and Northeast Asia. His analysis of this complex issue is clear and understandable.
I quite agree with his emphasis on the two most vital considerations which would affect a decision on whether Japan should arm itself with nuclear weapons: (1) U.S. policies which affect Japanese perceptions of the U.S. nuclear umbrella and (2) the situation on the Korean peninsula.
I do not believe -- and never have believed -- that Japan would go nuclear except in reaction to a very powerful shock to its security system, such as loss of confidence in the U.S. protective relationship or development of nuclear weapons in Korea in a manner that seems to threaten Japan.
As for U.S. policy, Halperin has stated the alternatives. I think ambiguity is likely to continue, and I agree with Halperin's caution about the impact of drastic changes.
I am less certain about his views on Northeast Asia. Although the development of a Northeast Asia nuclear free zone is a desirable goal, as is the creation of a regional security organization, I doubt either is possible so long as the current regime in North Korea is in power. The DPRK has rejected participation in regional activities, even on the Track Two level, apparently out of concern that it will be in a disadvantageous position in meetings with stronger regional powers and the ROK. China has been unwilling to participate without North Korea. The only practical possibility I can see at the moment is expansion of the existing four-party talks to bring in Japan and Russia, as proposed by ROK President Kim Dae Jung. This would not be easy but, if it happened, might provide a forum that could ease into regional security issues.
In my view, greater policy emphasis should be placed on working with the ROK to forestall development or possession of nuclear weapons after unification. However and whenever unification occurs, the present ROK is certain to be the dominant power. Currently ROK policy is to remain free of nuclear weapons, but there is a substantial body of opinion -- greater and more powerful than that in Japan -- which does not agree. Throughout the 1990s the United States has been doing all it can to stop or stall the North Korean nuclear weapons program, so far, I believe, successfully. In the longer run it also needs to turn its attention south of the DMZ. In the mid-1970s the United States used strong pressure, bordering on coercion, to halt a South Korean nuclear weapons program. It could not exert the same pressures following unification, although the stakes in the future will be equally high -- in the first instance, the military status of Japan.