This essay reviews the status of nuclear threat in Korea and analyzes the appropriate policy response to the emergence of the DPRK as a nuclear-armed state. We suggest that as of 2009, the DPRK made the ROK the main target of its nuclear strategy rather than the USA, as was the case from 1991–2009. The sinking of the ROK corvette Cheonan in 2010 provides a mini-case-study of the collision of ROK and DPRK historical trajectories, and portends continuing clashes involving nuclear threat that need to be managed to avoid escalation to nuclear next-use. The artillery attack on Yeonpyeong Island in November 2010 may be the second in what proves to be a series of such risky provocations. We conclude the paper by outlining the advantages of a ROK–Japan-only nuclear-weapon-free zone relative to alternative ROK responses to the threat posed by the DPRK nuclear breakout. In an Epilogue, we reflect on the methodological difficulties posed by the DPRK in interpreting its nuclear statements.