Ex Aequo Et Bono: The Uses of the Road Never Taken

Abstract

The International Court of Justice (ICJ) can decide cases either according to the sources of international law (the law route) or—if the parties so choose—according to justice, "ex aequo et bono" (the justice route). The ICJ has never issued a judgment in the justice route, which indicates that no pair of parties simultaneously agreed to choose that option. This raises two questions: (1) Why do parties never choose the justice route? (2) Does the justice route serve any purpose despite its disuse? The paper suggests that the existence of the justice route does help the ICJ to promote the peaceful settlement of disputes. The justice route can serve a screening function: a party that chooses the justice route signals to the other party the weakness of its case and thus indicates that it is likely to accept a low settlement offer. These parties will settle out of court, which explains the lack of judgments in the justice route. When parties decide to choose the law route, they also signal their loyalty to international law and thus improve their international reputation. Finally, the presence of the justice route helps frame the law route as more legally constrained. It thus helps the ICJ to project that it applies the law instead of making policy.

Keywords: International Court of Justice, Dispute Settlement, Screening

JEL Classification: K41, K33