【摘要】 自民族国家体系形成以来,主要大国经常以缔结、变更和扩展联盟的方式,改变国际体系中的实力对比,增强在大国安全竞争中获胜的前景,从而在国际秩序的塑造过程中占据有利地位。第二次世界大战结束后,美苏两个超级大国之间的对抗导致国际体系分化为两个对立的阵营,两国主导建立的两个联盟体系发展成为政治、经济、安全和意识形态高度一体化的架构,从而维持了两极均势秩序和两个阵营内部的等级秩序。在两极竞争中,联盟的灵活性显著降低,从一种应对安全威胁的合作形式转变为超级大国维持自身主导秩序的工具。冷战结束后,美国主导的联盟体系不仅没有弱化,反而不断调整战略、扩展成员、强化功能,成为美国维持单极霸权的重要支柱。随着国际权力结构朝着分散化方向发展,美国领导下的庞大联盟体系受到利益诉求差异、成本分摊矛盾和战略承诺模糊等因素制约,增大了美国协调和管理盟友战略行为的难度,也影响到单极霸权秩序的稳定性。更多还原

【Abstract】 Since the emergence of nation-state system,great powers have attempted to alter the balance of power through forging,shifting,and expanding alliances to increase their prospect of winning the security competition,and then obtaining a favorable position in the formation of international order. After the end of the World War II,the United States and the Soviet Union had engaged in an all-out confrontation,diving the international system into two competing blocs,each of which had highly integrated in the political,security,economic,and ideological domains.These arrangements had sustained a balance-of-power order between two superpowers on the one hand and two hierarchical orders within their respective blocs on the other hand. Under the situation bipolar competition,alliances lost their flexibilities significantly since they became instruments to dominate and maintain the orders the two superpowers led,instead of being a form of cooperation to address security threats. In the post-Cold War world,a vast alliance system led by the United States has not only been sustained but also enhanced through strategic adaption, membership enlargement,and functional adjustment. The alliance system,composed of both multilateral and bilateral treaty allies,is undeniably one of the most important pillars of US hegemony. With the international system getting decentralized,the cohesion and effectiveness of the US-led alliance system has been hampered by a number of constraints, including diversified interests among allies,disputes over burden sharing,and the ambiguity of strategic commitments. Under the Trump administration,it is apparent that the United States faces difficulties to coordinate and manage its allies ’behavior,whilst endangering the stability of the US hegemonic order.更多还原