Partisanship, Military Constituencies, and District Competitiveness Explaining Congressional Opposition to the International Criminal Court

In May 2020, bipartisan groups of US representatives and senators joined public letters criticizing the International Criminal Court (ICC) after it opened an investigation in Afghanistan and moved toward opening an investigation in Palestine. Why did some members of Congress join these letters, while others did not? This paper develops and tests a theory focusing on two factors to address this question: partisanship and the interaction between electoral competitiveness and military constituencies. First, building on literature identifying partisan differences in attitudes toward the ICC and international organizations more generally, we first expect that Democrats should have been less likely to sign these letters. However, partisanship is insufficient to explain intraparty variation among Democrats in joining these letters. To this end, we propose that Democrats representing electorally competitive constituencies with a significant military presence should have been more likely to join these letters in order to appeal to military voters with concerns about ICC prosecutions targeting US military personnel in Afghanistan (and elsewhere). We test this theory with respect to the House letter, and we find evidence supporting our hypotheses. We also find that representatives of districts with substantial Jewish populations were more likely to join the letter, which also called for action to protect Israeli nationals from prosecution in the situation in Palestine. These findings provide insight into not only individual representatives’ positions on the ICC but also the role of partisanship and sources of bipartisan agreement on US foreign policy.