特朗普执政以来美国联盟政策的调整

Adjustment of US’ Alliance Policy in the Trump Era

联盟既是美国遏制竞争对手的主要依托,也是其维持自身在联盟内部主导权的重要工具。在“美国优先”理念的指引下,特朗普执政后美国的对外战略发生了较为明显的变化,联盟在美国外交事务中的重要性下降。但美国仍然尝试通过转嫁成本的方式来维护其在联盟体系中的优势地位。联盟成本分担问题成为特朗普向其盟友“开火”的抓手。在特朗普的高压态度下,部分盟友已增加了军费支出。同时,特朗普执政后美国的联盟政策更为务实,不再刻意追求美国与盟友之间在意识形态和制度上的契合。然而,由于特朗普的外交政策缺乏连贯性和一致性,美国传统盟友开始质疑其治下美国的战略信誉。其盟友或被迫选择“自力更生”的内向型策略,亦或选择“对冲风险”的外向型策略来应对特朗普政策所造成的不确定性。

Forming alliances has been both the main foundation of the US to contain competitors and a core instrument for maintaining its leadership among its allies.Led by the“American First”narrative,the US foreign policy strategy in the Trump era has undergone some observable changes,and the significance of alliance has declined.However,the US still tries to maintain its dominance by passing on to its allies relevant costs.Alliance cost-sharing has become a key issue for the Trump administration to exert pressure on its allies.Under this circumstance,a number of US allies have reacted accordingly and raised their contribution to common defense.Meanwhile,the US alliance policy has gradually become more pragmatic and the Trump administration has no longer sought to share ideological and institutional system with its allies.However,due to the lack of coherence and consistency of Donald Trump’s foreign policies,traditional allies of the US have begun to question the strategic credibility of the US.They may be forced to choose an inward strategy of“self-reliance”or an outward strategy of“risk hedging”to counterbalance the uncertainties caused by Trump’s foreign policies.