Assesses the probabilities that Japan, Taiwan or South Korea might develop nuclear weapons, and what the consequences of proliferation might be for the People's Republic of China (PRC). The possibility that any of these states might embark on a nuclear weapons program is remote because of the political, diplomatic, and military costs, which outweigh any advantages from an independent nuclear capability. Should proliferation nevertheless occur in Japan, Taiwan, or South Korea, it would indicate a substantial loss of faith in the American security role. China has abstained from transferring nuclear technology to other countries. If proliferation seemed underway on China's periphery, this could be deleterious to China's interests, although PRC leaders remain ambivalent or noncommittal on how they might react to such a possibility.