本文以國際關係學界的失衡觀點研究為探討主題，該研究衍生自現實主義學派平衡理論體系，在該理論基礎上嘗試反向論證美國自冷戰後期以降長盛不衰的國力優勢，使國際體系呈現長期穩定的失衡狀態，無論是權力平衡或柔性平衡理論邏輯，皆因過於巨大的國力差距而無法適用於當代美國。循此，失衡觀點研究者主張美國外交施政應擺脫對外部平衡反應的過多顧慮，同時克服孤立主義誘惑，對國際事務保持深度而穩定的參與，藉以維護國家安全和利益。作為新興研究議題，失衡觀點因具一定學術創新意義而漸受學界關注，但亦存在部分有待進一步探討的模糊空間。本文回顧了該研究的演進脈絡和核心論點，並運用其分析美國近年外交政策動向，藉以檢證其政策參考價值、不足之處及後續可能的發展方向，期能促進該研究的持續進化。

This article has explored the perspective of "Out of Balance" of international relations studies. The "Out of Balance" perspective was derived from the "Balance Theory" of the school of Realism, while affirming the essential ideas of the "Balance Theory", it also emphasizes the power advantage of the United States in the post-Cold War era has made the current international system present a stable state of imbalance, neither the logic of “Balance of Power” or “Soft Balancing” can be applied to the United States. Researchers of the "Out of Balance" perspective thus advocated that the U.S. foreign policy should get rid of concerns about systematic constraints, try to resist the temptation of isolationism, and maintain a deep engagement in international affairs, to protect its national security and interest. Over the past two decades, the "Out of Balance" perspective research has gradually gained attention in the field of international relations studies, although it has certain academic innovation significance, due to the relatively short time of development, the current research still has some imperfections. This article has reviewed the development context and the main contents of the "Out of Balance” perspective, then use it to analyze the trend of U.S. diplomacy in recent years, so as to verify its policy suggestions value, the shortcomings of current research, and propose possible ways to improve, expect to promote the progress on this new research issue.