This chapter aims to analyze whether South Korea’s rapprochement policy toward North Korea—exemplified by its “Sunshine Policy”—represents a revisionistic approach in contrast to traditional approaches such as “security through strength,” and to derive lessons from this analysis. It reviews the concepts of revisionism and revisionistic approaches in national security and examines recent South Korean government policies concerning North Korea’s nuclear armament. The chapter argues that South Korea’s rapprochement policy may indeed constitute a revisionistic approach, which has failed to achieve meaningful results despite its promises to resolve most issues between the two Koreas through dialogs. As of 2025, the two Koreas are highly confrontational, with no dialog, meetings, or economic exchanges taking place, and North Korea openly threatening to attack and annex South Korea with nuclear weapons. South Korea’s experiment and subsequent failure serve as a valuable lesson for other revisionistic approaches in international relations. It is particularly important that revisionistic theories be thoroughly debated in academic settings before being applied in practice, and that they be balanced with traditional approaches.