Decision Making on the World Court: Are International Judges Geopolitically Biased?

Do international adjudicators align with the foreign policy interests of their home country? This article contributes new evidence that judges on the International Court of Justice (ICJ) diverge along similar lines as their home states in the United Nations General Assembly (UNGA). Ideal points for judges and countries are estimated from nonunanimous judicial votes up to January 2023 using Item Response Modelling and then related to country ideal points estimated from UNGA votes in earlier research. The analysis reveals that, as with countries in the UNGA, a pro-anti-Western divide order constitutes the main dimension of disagreement on the Court. Moreover, ideal points derived from UNGA voting patterns are themselves robust predictors of voting affinity among judges as well as between judges and the parties involved in litigation. Judges originating from nations exhibiting greater geopolitical divergence are more likely to disagree. Just as judges from more pro-Western states are less likely to favour anti-Western litigant states.