ABSTRACT
The most substantial of all bars to the acquisition of nuclear explosives is a sense of adequate security. Some countries are fortunate enough to possess it in large measure through an accident of geography or the lack of regional adversaries. For others, security lies in alliance ties, sometimes backed up by the presence of allied forces or even their nuclear weapons. Nuclear guarantees, especially by the great powers, are of central importance for the security and stability of Europe and other regions as well as Japan. Universal principles have the great merit of generating wise legitimacy. Prohibitions against commercial use of plutonium or highly enriched uranium anywhere, against international transfers of reprocessing technology, and against all "peaceful" nuclear explosions are examples of proposed universal rules in the nuclear sector. The prospects for economic use of nuclear energy differ widely; so does political stability.
