South Korea’s security discourse on the nuclear threat posed by North Korea has been dichotomised by its position within the political spectrum between the progressives and conservatives. By drawing upon Securitisation Theory (ST), this study challenges the current security discourse in South Korea, which has divided and misled the public as well as securitising actors. This study examines the security discourses of the Roh Moo-hyun (2003–2008) and Lee Myung-bak (2008–2013) administrations, since they represent the archetypes of the progressives and conservatives respectively. The results of the analysis suggest that the current security discourses that have been prevalent in South Korea do not correspond with reality and, subsequently, the discourses were not able to deal with real challenges that the nuclear threat posed. This research also explains the root cause of the distorted security discourses by applying a ‘discursive chasm’ as a preliminary concept, which indicates a discursive structure that fundamentally impedes the performance of securitising actors’ articulation, and that distorts the discursive formation (securitisation processes). The chasms consist of three elusive discourses: first, a discourse on threats that cannot simply be said to be either imminent or not imminent (nuclear weapons as materiality and discourse); second, a discourse on the other that cannot easily be defined (the difficulty of representation of North Korea); and third, a discourse on measures that cannot easily be realised (intangible extraordinary measures).

South Korea’s security discourse on the nuclear threat posed by North Korea has been dichotomised by its position within the political spectrum between the progressives and conservatives. By drawing upon Securitisation Theory (ST), this study challenges the current security discourse in South Korea, which has divided and misled the public as well as securitising actors. This study examines the security discourses of the Roh Moo-hyun (2003–2008) and Lee Myung-bak (2008–2013) administrations, since they represent the archetypes of the progressives and conservatives respectively. The results of the analysis suggest that the current security discourses that have been prevalent in South Korea do not correspond with reality and, subsequently, the discourses were not able to deal with real challenges that the nuclear threat posed. This research also explains the root cause of the distorted security discourses by applying a ‘discursive chasm’ as a preliminary concept, which indicates a discursive structure that fundamentally impedes the performance of securitising actors’ articulation, and that distorts the discursive formation (securitisation processes). The chasms consist of three elusive discourses: first, a discourse on threats that cannot simply be said to be either imminent or not imminent (nuclear weapons as materiality and discourse); second, a discourse on the other that cannot easily be defined (the difficulty of representation of North Korea); and third, a discourse on measures that cannot easily be realised (intangible extraordinary measures).

The thesis describes Korean Peninsula political development from 1998 to 2008, in the frame of historical context from 1948 when two independent states were oficially founded. Discussed decade was characterized by the policy of engagement or the sunshine policy of the Republic of Korea, respectively. This represented a concept of friendly relationship towards the DPRK, aiming at final unification. Detailed description of the political development year by year and its evaluation is the subject of this thesis.

二次世界大戰時，美國擊敗日本，使朝鮮半島脫離殖民統治，然而隨後的美蘇冷戰，使得朝鮮半島分裂成南北兩韓，而美國與南韓簽訂條約，成立美韓同盟(U.S.–South Korea Alliance)，成為繼日本之後，美國在亞洲的另一個戰略同盟。冷戰與後冷戰期間，美韓關係雖有波折，但不影響美韓同盟的強度。直到2000年美國小布希就任，其強硬的北韓政策與南韓金大中的陽光政策形成對比，成了美韓關係不協調的開端。而後連任的小布希延續其北韓政策，南韓繼任的盧武鉉將陽光政策擴大實施，推出和平繁榮政策，美韓兩國的北韓政策再度不同調，兩國關係持續跌宕起伏至2008年。本研究試圖以攻勢現實主義分析美國此時期的北韓政策；以新自由制度主義檢視南韓的交往政策，透過理論交鋒研究兩國利益的差異，並檢視外部因素如中國、日本、俄羅斯的影響，進而解釋此時期美韓關係不協調的原因。 / In 1945, the U.S. defeated Japan. The Korean peninsula was liberated from Japanese colonization at the end of World War II. However, the confrontation between the U.S. and the Soviet Union left two Koreas separated by the Demilitarized Zone from the Cold War to the present. In addition, based on the Mutual Defense Treaty Between the United States of America and the Republic of Korea, the U.S.–South Korea Alliance was established. During the Cold War and Post Cold War era, the U.S.-South Korea relations faced hard times, but the alliance remained strong. When George W. Bush became the president of the U.S. in the year 2000, his hardline policy toward North Korea collided with South Korea’s Sunshine Policy, which was made by the president Kim Dae-jung. These different policies toward the North caused tensions to the U.S.-South Korea relations. Then the re-elected Bush continued hardline policy against North Korea, but South Korea’s new president—Roh Moo-hyun—decided to inherit the sunshine policy and develop Peace and Prosperity Policy. Washington and Seoul still failed to reach a consensus on how to deal with Pyongyang. The U.S.-South Korea relations continued to fluctuate until 2008. This study tries to analyze the U.S. policy toward North Korea through offensive realism and examine South Korean engagement policy through neoliberal institutionalism from 2000 to 2008. Besides, this thesis also considers exogenous factors such as China, Japan, and Russia, trying to explain the inconstancy of the U.S.-South Korea relations.