在美中競爭的背景下，美國陸續強化與印太盟邦與夥伴的關係。一方面提高美日印澳四方會談的層級，二則宣布與英澳締結新協議。美國的行動引發圍堵政策再起的討論，以及印太是否會出現多邊安全同盟的疑問，本文考察四方會談以及美英澳協議的目標與本質，研究發現這些安全機制距離冷戰時期的圍堵政策仍有一段距離。這些機制本身未具有同盟的功能，且成員尚未能對各自關切的安全事務作出承諾。四方會談與美英澳協議皆為具有彈性且不具安全承諾的合作，經常作為外交團結的表徵，而非介入安全事務的保證。印太在可預見的未來內還不會出現多邊安全同盟，也還不會出現類似冷戰的集團對抗。

The US continues to strengthen its relations with Indo-Pacific allies and partners as it competes with China. The US strengthened the Quadrilateral Security Dialogue with Japan, India, and Australia; it also announced the AUKUS agreement with UK and Australia. These actions raise a discussion over the return of containment policy and the question of emerging multilateral security alliances in Indo-Pacific. This article explores the goals and substances of the Quad and AUKUS. It is argued that these security mechanisms are not similar to the containment during the Cold War. These mechanisms do not have the function of treaty alliances, and members fails to commit to the security affairs each country is concerned. The Quad and AUKUS are flexible cooperation that do not involve security commitment. States use them as symbols of diplomatic unity rather than promises of intervention in security affairs. There will be no multilateral security alliances for the foreseeable future. The Cold War-style bloc confrontation is also unlikely.