國際關係主流理論研究的是多邊關係，但是多邊關係得以運作，其前提在於，當多邊關係受限時，可仰賴雙邊關係加以維繫或超越，使多邊關係免於遭到直接挑戰。本文主張將雙邊關係做為國際關係研究途徑加以探究，並以戰後英國因實力變化而選擇轉向雙邊為個案。出於避免一夕崩壞及維護利益的設想，孱弱的大英帝國在戰後選擇向雙邊主義靠攏，美中兩國成為優先考量。即便這兩組雙邊關係間存在矛盾，卻是英國勉強藉由兩組雙邊關係維繫既有多邊框架，再行逐步調整，進而在戰後世界站穩腳跟的機制。

Mainstream IR theories are typically multilateral. However, for any multilateral frame or value to last, bilateral relations must be able to resolve conceivable limitations. Thus, bilateral relations should be intrinsic to IR theorization. We use the United Kingdom in the aftermath of WWII as our case. The UK managed bilateral relations with the United States and China as ways to overcome its decline after the war. The bilateral relations transcend the multilateral frame and value. Accordingly, the UK’s two bilateral relations are inconsistent, but together are conducive to maintaining UK’s nominal status which has been challenged under its extant multilateral frame.