Document Type


Publication Date



This Article examines a category of conduct that I call “unfriendly unilateralism.” One state deprives another of a benefit (unfriendly) and, in some cases, strays from its own obligations (noncompliant), outside any structured international process (unilateral). Such conduct troubles many international lawyers because it looks more like the nastiness of power politics than like the order and stability of law. Worse, states can abuse the conduct to undercut the law. Nevertheless, international law tolerates unfriendly unilateralism for enforcement. A victim state may use unfriendly unilateralism against a scofflaw in order to restore the legal arrangement that existed before the breach. Unfriendly unilateralism is tolerated here, despite its unsavory attributes, because the formal processes for enforcing international law are often deficient. Unfriendly unilateralism can compensate for that procedural deficiency and help make the law effective.

This Article argues that unfriendly unilateralism can play a similarly vital role in lawmaking. The Article makes both a positive and a normative claim. The positive claim is that, in practice, states use unfriendly unilateralism not only to enforce but also to help generate law. Unfriendly unilateralism variously helps create new norms, prevent the erosion of existing norms, reconcile competing objectives, and strengthen or recalibrate regimes. Unfriendly unilateralism sometimes performs these functions even when the conduct itself is unlawful — that is, when the conduct is noncompliant and unexcused for enforcement. The Article’s normative claim is that such unchecked and even unlawful exercises of state power can be good for international law. Lawmaking allows the legal order to stay relevant and adapt to change. However, the formal processes for making international law, like those for enforcing it, can be deficient. Unfriendly unilateralism can compensate for that procedural deficiency and help instigate or support collective decisions.