In view of the changing security environment in Northeast Asia, stemming fromChina’s assertiveness in regional issues and North Korea’s nuclear weapons program,the threat perception in Japan has considerably heightened. This has triggered adebate domestically in Japan about whether it is an appropriate time to review itsnuclear option as a means of deterrence. Such thinking presupposes that confidencein the U.S. extended deterrence has started eroding or has weakened. There arevarious political strands to this issue and there is no consensus yet reached to makethe change officially possible. If Japan does indeed initiate a change in policyseriously, it would make the United States uncomfortable. But given the stronganti-nuclear sentiment in Japan, it would be difficult for any government of anyparty to sell the idea to the people. The domino effect of such a policy changewould be seen almost immediately in South Korea and Taiwan, making NortheastAsia the world’s most nuclearized region. This would also mean the abrogationof the security alliance relationship with the United States. Given Japan’s capabilityin terms of capital, technology and possession of sufficient spent fuel needed formaking the nuclear bomb it would be possible for Japan to make a nuclear bomb,but it would be a politically dangerous move and therefore inadvisable. Though itwould remain theoretically possible, the debate would remain as an academicexercise for quite some time. This essay makes an attempt to study this complexissue as objectively as possible.