This project looks at cross-national similarities and differences in the way in which international law is understood, interpreted, applied, and approached by different actors in and from different states. Lawyers are used to employing comparative approaches when dealing with national laws and domestic legal systems because it seems obvious that these might differ in interesting ways or that some approaches might be similar based on factors such as language, colonial history, and membership in the same legal family. But lawyers do not typically employ comparative law approaches when it comes to international law because the field’s universalist assumptions and ambitions makes the search for national differences seem both less obvious and potentially threatening.

During the Cold War, it was common for lawyers to refer to Soviet and Western approaches to international law, which made sense given that there were two superpowers with rival approaches to international law. However, after the fall of the Berlin Wall and the rise of the United States as a unipolar power, it was more common to find a universalist approach that discounted differences as aberrations from the norm. However, as the world moves into an age of declining US and Western power and rising multipolarity, it seems likely that discussions of particular national or regional approaches from different great powers will again become an important feature of international law discussions. This is occurring with certain contemporary issues, such as the law of the sea and cyber security.

Related publications include symposium on Comparative International Law ((2015) 109 American Journal of International Law 467), an edited collection (Comparative International Law, Oxford University Press, 2017) and Anthea Roberts’ monograph Is International Law International? (Oxford University Press, 2017).