Polarization has been a prevalent phenomenon in US politics, yet its foreign policy implications remain understudied. A common assumption is that polarization undermines the utilization of United States’ material power via a coherent grand strategy. In this article, I argue that polarization does not make the United States incapable of enacting a foreign policy per se but instead affects US foreign policy conduct, power, and strategy toward international negotiations. The effects of domestic polarization for US foreign policy behavior in international negotiations are best understood via an advanced application of the “two-level game” model, which conceptualizes a state's domestic politics as a determinant factor for the executive branch's approach toward foreign affairs. I identify three effects polarization has on US foreign policy: (1) a sorting effect, which produces homogenous partisan coalitions with divergent foreign policy preferences and inclines the executive to pursue an obstinate international negotiation conduct; (2) a partisan conflict effect, which weakens Congress as a veto player and reduces United States’ bargaining power; and, finally, (3) an institutional corrosion effect, which inclines the executive branch to manipulate domestic support and to politicize international negotiations at home. In sum, domestic polarization increases the opportunity costs for US foreign policy toward international negotiations and contributes to global instability. Anecdotal evidence from US foreign policy over the last decade offers support for these effects, but further empirical research is needed to better understand when they are most impactful and in which combination these effects appear.

中文翻译：

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将两极分化对国际谈判中美国外交政策行为的影响概念化：重新审视两级博弈

两极分化一直是美国政治中的一种普遍现象，但其外交政策影响仍未得到充分研究。一个普遍的假设是，两极分化通过连贯的大战略破坏了美国物质力量的利用。在本文中，我认为两极分化并不会使美国本身无法制定外交政策，而是会影响美国的外交政策行为、权力和国际谈判战略。国内两极分化对国际谈判中美国外交政策行为的影响最好通过“两级博弈”模型的高级应用来理解，该模型将一国的国内政治概念化为行政部门处理外交事务的决定因素。我确定了两极分化对美国外交政策的三种影响：(1) 排序效应，产生具有不同外交政策偏好的同质党派联盟，并倾向于执行顽固的国际谈判行为；(2) 党派冲突效应，削弱国会的否决权，削弱美国的议价能力；最后，（3）制度腐蚀效应，使行政部门倾向于操纵国内支持并将国内的国际谈判政治化。总之，国内两极分化增加了美国外交政策对国际谈判的机会成本，并助长了全球不稳定。过去十年美国外交政策的轶事证据支持这些影响，