The main goal of this article is to analyze the conditions under which South Korea would decide to go nuclear. It seeks to examine the key factors that would trigger Seoul's decision for nuclear-arming. The article contends that South Korea is likely to go nuclear under the following conditions: where South Koreans' demands for nuclear weapons continue to rise despite US security assurances; where Pyongyang's threats of its nuclear weapons attacks are increasingly directed towards Seoul as opposed to Washington; where US security assurances for South Korea become highly questionable; and where potential nearby proliferators (Japan and Taiwan, in particular) go nuclear. Any single one of these conditions might not be enough for Seoul's decision to nuclearize, but when at least any two of them are fulfilled at the same time, South Korea is highly likely to go nuclear.