美國自1990年代初期的第一次核武危機至今,共歷經了四任總統,然而卻在北韓核武問題上遲遲無法有所突破。北韓至今共進行了六次的核試爆,甚至已具備發射洲際導彈的能力,威脅持續升高。然而自六方會談破局後,國際間再沒有類似的多邊機制,能夠藉由主要相關國家的力量來共同形塑北韓的行為。在缺乏多邊機制的情況下,延伸性嚇阻儼然成為美國政府面對北韓問題的主要手段之一,以阻止北韓採取破壞現狀,威脅東北亞區域的安全。 本文研究目的主要針對美國延伸性嚇阻對東北亞區域安全之重要性、六方會談敗局後美國對北韓政策轉變、及歐巴馬與川普政府對北韓政策之異同與盟國反應等問題進行探究,透過文獻分析及比較研究法,並以嚇阻理論作為研究途徑,試圖比較歐巴馬與川普政府對北韓之政策。筆者藉各項文獻之梳理,列舉出「核武運用」、「傳統武力運用」、「結盟」與「國際制度」等各項國家領導人能夠影響延伸性嚇阻成效之因素,作為比較兩任政府對北韓政策之指標。 歐巴馬政府上任之初曾試圖爭取重啟六方會談,惟北韓態度的反覆轉變以及不守承諾,導致歐巴馬對北韓政策逐漸轉趨為強硬的制裁與冷漠的應對,形成「戰略忍耐」政策。而川普上任後,大肆批評歐巴馬的北韓政策,認為其縱容北韓不斷地取得核武及導彈能力的進展,因而採取「極限施壓」政策,主張加強對北韓的制裁,並且不排除使用有限度武力,逼迫其重回外交對話。北韓問題雖未在歐巴馬或川普政府期間得到明顯改善,然若以延伸性嚇阻的角度作檢視,可發現相較於川普政府,歐巴馬政府的北韓政策較符合學術界對延伸性嚇阻的定義,對於東北亞區域安全穩定的維持亦較有正面影響。
The United States has been through four administrations since the first North Korean nuclear crisis in the 1990s, yet it has still not been able to make a significant breakthrough on the North Korea nuclear issue. North Korea has conducted 6 nuclear tests by far and even claimed to have ICBM capabilities, which posed increasing threats in the region. Ever since the six-party-talks ended, the international society has been lacking a multilateral mechanism alike that can get key relevant countries together to shape North Korea's behavior. With a lack of multilateral mechanism, extended deterrence thus became one of the primary means that the U.S. government can rely on when it comes to North Korea issue. The purpose of this study was to analyze issues including the importance of U.S. extended deterrence to North East Asia security, the U.S. North Korea policy shift since the end of the six-party-talks, and the similarities and differences between Obama and Trump administrations' North Korea policy and the reactions of allies. Document analysis and comparative research methods were applied as research methods, and deterrence theory was utilized as research approach in this study. Several factors that can have impacts on the effectiveness of extended deterrence such as employment of nuclear weapons, employment of conventional forces, allies, and international mechanism have been listed as indicators for comparing these two administrations' North Korea policy. Obama administration initially attempted to get back to the six-party-talks, but the capricious attitude and untrustworthiness of North Korea regime caused the adoption of "strategic patience" policy, meaning the policy of tough sanctions and indifferent responses. Since Trump took office, he had criticized Obama's North Korea policy and believed it had only allowed North Korea to incessantly advance its nuclear and missile capabilities, and therefore decided to adopt "maximum pressure" policy that was aimed at ramping up the sanctions and pushing North Korea back to diplomatic dialogue with considerations of using limited military force. Although North Korea problem has not been solved during Obama or Trump administration, Obama's North Korea policy seemingly met the academic definition of extended deterrence better than Trump's, and it also had more positive impacts on maintaining North East Asia security.