冷戰後美國的台海嚇阻戰略

Abstract

嚇阻理論是一個成長於冷戰期間的國際關係理論。冷戰結束後，一般嚇阻的趨勢更為凸顯，加上軍事事務革命的出現，影響了嚇阻理論的發展。在此背景下，探討嚇阻理論在台海地區的運用，具有學術性與政策性的價值。 本文認為，美國在台海地區進行嚇阻的原因主要係台海爆發潛在衝突的本質及美國在此地區之國家利益。前者包括兩岸之間的主權爭議、制度差異、互信缺乏及軍備競賽，使兩岸日益陷入安全困境；美國在台海的國家利益則有維持區域影響力、與新興強權交往、維護區域安全、嚇阻侵略、防止挑釁等。本文認為，台灣不是美國攸關利益地區，但台海安全影響了美國的攸關利益，所以美國必須在台海地區進行嚇阻。 美國在台海嚇阻之戰略思維，係欲配合其全球戰略，防止潛在競爭者實力的崛起，挑戰其國家利益，另則要嚇阻區域侵略者，以維持其區域影響力及其在盟邦之間的信譽。事實上，美國的嚇阻戰略從「一套應付所有衝突的嚇阻戰略」（“one size fits all” deterrence），轉變為「多層次嚇阻戰略」（strategy of “layered deterrence”），再轉變為「量身訂製的嚇阻」（tailored deterrence）。在嚇阻的政策工具上，美國採取了亞太兵力部署調整、強化亞太盟邦、展示武力（demonstration of force）、對台軍售、研發部署飛彈防禦系統、發表嚇阻言論等手段，來防止兩岸任一方挑釁對方，破壞現狀。對於美國的嚇阻戰略，中共認為美國想追求及維持霸權，圍堵中共及阻止兩岸統一，所以美國要調整亞太兵力部署，與盟邦聯手嚇阻中共，使中共相當力量和資源消耗在「台灣問題」上，並藉武力展示為武力干涉「台灣問題」做準備，但隨中共日益認為美國係進行雙重嚇阻後，其反應漸從排斥、敵對，轉為配合、拉攏、協調，在宣傳上避免與美國針鋒相對，軍事規劃上則重長期發展，建立反嚇阻戰略與自主應付危機之能力。台灣認為美國的嚇阻戰略對中共較具針對性，認同美國關於中共軍力發展顯然超出合理防衛需求之觀點，把中共視為台灣與美國的安全威脅，此外，台灣自認為美國在東亞不沈的航空母艦，美國不希望台灣淪於中共之手，加上台灣與美國同屬民主國家，若台海發生戰事，美國可能前來馳援。針對美國對台灣發出之嚇阻言論，台灣曾向美國保證不會挑釁北京，多次重申對大陸政策不變，且屢次強調要加強對美溝通。 針對上述情勢發展，本論文試圖從「威脅v.s.再保證」、「威脅、中立、結盟」等嚇阻工具之組合，以及「戰略模糊v.s.戰略清晰」三個層次，建構起雙重嚇阻之理論架構，將美國在台海之嚇阻戰略模式，區分為「雙重明確嚇阻型」、「模糊明確參半型」、戰略清晰下之「兩面為敵型」、戰略模糊下之「兩面為敵型」、騎牆策略型與利害之交型等類型，本論文認為，對現狀解釋力最強者係「騎牆策略型」，亦即美國以「與台灣結盟」來嚇阻中共，以「對台海衝突保持中立」來嚇阻台灣，嚇阻效力最強者則為「雙重明確嚇阻型」，亦即對中共與台灣均明確劃下不可觸犯之行為底線。 本論文的結論是，鑑於美國在台海的嚇阻戰略運用與發展日趨成熟，雙重嚇阻將可持續相當長一段時間，除非中共挑戰美國嚇阻戰略的軍事能力或台灣追求法理獨立的意圖成長過於快速，雙重嚇阻之架構才會崩解。

Deterrence theory developed in the Cold War era. After the end of the Cold War, the trend of “general deterrence” prevails, along with the emergence of “revolution on military affairs”, which affects the development of deterrence theory. Under such circumstances, the discussion on the application of deterrence theory in the Taiwan Strait is valuable for academic and policy reasons. The dissertation asserts that the reasons for the United States to deter conflict in the Taiwan Strait are mainly because of the nature of potential conflict and national interest in the region. The former includes sovereignty dispute, institutional differences, absence of mutual trust, and arms races between both sides of the Strait. The latter includes maintaining regional influence, engagement with an emerging power, protecting regional security, deterring invasion, and preventing provocation by either side. The author argues that Taiwan is not of vital interest for the United States; however, the security in the Taiwan Strait affects the vital interest of the United States, which is why the United States has to deter the conflict in the region. As far as the deterrence strategy in the Taiwan Strait is concerned, U.S. deterrence thinking collaborates with its global strategy to prevent the rise of potential competitors from challenging its interests, as well as to deter regional invader to maintain its regional influence and reputation among allies. As a matter of fact, U.S. deterrence strategy evolves from “one-size-fits-all” deterrence to strategy of “layered deterrence”, then turns to “tailored deterrence”. As for the tools of deterrence, the United States uses the readjustment of force deployment in the Asian Pacific, the realignment of Asian Pacific allies, demonstration of force, arms sales to Taiwan, the development and deployment of missile defense systems, the declaration of deterrence rhetoric to prevent either side from provocation and any endeavor to spoil the status quo. China’s perception of U.S. deterrence strategy is that the United States intends to pursue and maintain hegemony, contain China and impede reunification of the nation, and therefore readjust its force deployment in the Asian Pacific and work with its allies to deter China to deplete China’s strength and resources in the “Taiwan issue”, and prepares for military intervention through the demonstration of force. Nevertheless, as a result of the gradual awareness of US’s dual deterrence, China has shifted from rejection and rivalry to cooperation and appeasement. China avoids direct confrontation with the United States on its propaganda and emphasizes long-term development in military planning to build its own anti-deterrence strategy and capability to cope with crisis. Taiwan regards U.S. deterrence strategy as hostile to China, and agrees with American view on China’s military development obviously exceeding reasonable demand for defense. Taiwan thinks that China is the common security threat of the United States and Taiwan. Taiwan believes that it is an unsinkable aircraft carrier of the United States in East Asia; thus the United States doesn’t want to see Taiwan fallen to the China’s control. Moreover, Taiwan and the United States are both democracies, so the United States might come to Taiwan’s rescue once war happens in the Taiwan Strait. In response to U.S. deterrence rhetoric, Taiwan has been assuring to the United States that Taiwan won’t provoke Beijing, claiming that its China policy remains unchanged, and reiterating its resolve to strengthen the communication with the United States. This dissertations tries to construct a framework from three levels of analysis: (1)threat v.s. reassurance, (2)the mix of means of deterrence - threat, neutrality and alliance, (3)strategic ambiguity v.s. strategic clarity. The author divides the patterns of deterrence in the Taiwan Strait into “Dual Clarity Deterrence”, “Twilight-Zone”, “Janus-Faced under strategic ambiguity”, “Janus-Faced under strategic clarity”, “Straddle Strategy”, and “Fair-Weather Friends”. The dissertation argues that “Straddle Strategy” pattern, meaning that U.S. deters China with possible alliance with Taiwan and deters Taiwan with neutrality in potential conflict, is the most powerful explanation for current situation. “Dual Clarity” pattern, meaning setting deadlines for China and Taiwan not to step over, is most effective. The dissertation concludes that dual deterrence could last for a long period of time because the U.S. has gradually acquired the “dual deterrence” savvy. The structure of “dual deterrence”, however, might collapse because of the rapid development of China’s military modernization to challenge the U.S. or of Taiwan’s intention to pursue de jure independence.