ROK–U.S. cooperation in preparation for hostile actions by North Korea in possession of nuclear weapons

Can the United States' extended deterrence guarantee the security of South Korea against nuclear threats posed by North Korea? North Korea manipulates its nuclear capability not only as a means of deterrence but also as a military leverage to threaten the very existence of South Korea. Considering the current pattern of North Korea's behavior and the geopolitical and strategic implications for the Korean peninsula, the U.S. promise of extended deterrence for South Korea appears to have many limitations. In fact, as demonstrated in the sinking of the ROK naval frigate Cheonan incident, North Korea, with its nuclear capability intact, now threatens South Korean security more openly. Accordingly, measures to increase the credibility of America's extended deterrence become ever more imperative such that it will act as a stronger deterrence against further aggressive actions by North Korea and give greater assurance to South Koreans. The U.S. extended deterrence statement in its Nuclear Posture Review (NPR) is not really adequate, being rather general in its tone and content. This article analyzes this credibility issue pertaining to the U.S. extended deterrence, along with the North Korean nuclear threats and their security implications, and finally proposes a series of measures and policy implications to enhance the ROK–U.S. security mechanism.