Abstract: The Asia-Pacific strategic landscape has been undergoing a profound transformation. As a dominant security actor in the region, the US security strategy has been a major driving force behind the changes, While defining China as the main competitor of the US in the Asia-Pacific region, the Obama administration was mainly concerned over China's rising geopolitical influence and sought to balance China; the first Trump administration paid special attention to China's growing military power and endeavored to suppress and contain China; and the Biden administration focused primarily on China's challenge to US security interests in the Western Pacific and maneuvered to deter China. Driven by a more proactive regional strategy and a relatively weaker power position since the Obama administration , the US has implemented an expansive alliance strategy, reshaping its traditional alliance system into a comprehensive network of allies and partners, Contemporary developments in the Asia-Pacific security order are characterized by the diversification of actor!and multi-dimensional balancing, leading to increased security interactions and the rising importance of Asian players, The future of Asia-Pacific strategic architecture hinges to a large extent on the evolution of Sino-US relations. The conflict between China and the US would result in a dissociated and confrontational regional landscape, while a Sino-US grand bargain would lead to a scenario characterized by the interplay among multiple actors with a blend of cooperation,hedging, and competition.

Keywords: US Asia-Pacific strategy, regional security, network of allies and partners, security landscape, Sino-US relations

Autho: WU Xinbo, Professor and Director at the Center for American Studies, Fudan University.