冷戰結束對於東亞區域安全造成深遠影響，雖然外在環境不再有兩強集團對峙，但東亞區域並未因冷戰結束，形成和平的氛圍，反而陷入安全困境(security dilemma)。主要原因為美國並未在東亞區域設立類似北約的多邊安全機制，而是透過與東亞國家的雙邊安排（舊金山體系），介入東亞區域的事務並維持權力平衡。美國透過政治面的人權外交，經濟面的經濟合作，以及安全面的雙邊同盟方式，來保障美國在東亞地區的政經利益。這種安排也符合東亞區域三大區域主義的發展節以美國為首的亞太主義、中共的大陸型東亞主義與日本的海洋型東亞主義，以及以東協為主的東協主義。短期而言，保持現有的美日澳安全機制，仍可維持東亞區域的穩定。長期而言，除非納入印度或直接納入中共，否則強化美日澳聯盟對於東亞安全機制的建構，將是一個非正向關係的選項。東亞區域安全機制之建構，其實是如何整合美國所欲維持的舊秩序與中共所欲創造的新秩序，同時東亞安全機制與美國霸權之間也存在一種反向的因果關係。

The end of the Cold War casted a lasting impact to the security in the East Asia region. Even though two superpowers cease to stand against each other in the external environment, it leads to a security dilemma rather than a peaceful setting in East Asia. This is mainly because the United States solely utilizes bilateral arrangements (San Francisco system) instead of creating a collective security institution like NATO in East Asia as means to achieve the balance of power in the East Asia region. The United States maintains bilateral alliances in the form of humanitarian foreign policy, economic cooperation and security issues to ensure its economic and political benefits. In the short run, maintaining the current US-Japan-Australia security alliance benefits the stability of East Asia security. In the long run, unless India and China are also included, it will be disadvantageous to the security in East Asia by strengthening the US-Japan-Australia security alliance. In fact, constructing the security in East Asia region it is actually the process to integrate the old order that US was trying to maintain and the new order that China is trying to create. All in all, there is a reverse causation between the collective security mechanism in East Asia and American hegemony.