Alex Wentker’s book, which will stand as the definitive work on co-party status for years, offers an extremely careful and comprehensive look at the nature and implications of being a co-party to an armed conflict. In addition to providing a range of insights about how to assess co-party status, his book prompted three reflections. One is a modest question about his approach to “collective contributions” of states to a conflict; the other two involve issues on which I think that he may have undersold the importance of his conclusions.
Citation
Ashley S. Deeks, The Power of Co-Party Influence on IHL Compliance (reviewing Alexander Wentker, Party Status to Armed Conflict in International Law) EJIL: Talk (2025).