In the last few years, states have advanced various proposals for cooperation in the use of countermeasures. In this Article, we ask whether, and if so under what conditions, states may lawfully collaborate in the taking of countermeasures against other states. We distinguish five different types of collaboration: (1) independent but coordinated action; (2) secondment; (3) joint action; (4) aid and assistance; and (5) what we term “proxy countermeasures”—the idea of taking a measure at the request and on behalf of another state. We consider the permissibility of each, both where the acting state is itself entitled to resort to countermeasures and where it is not. We also draw attention to certain legal and policy considerations relating to, and to plausible avenues for, the development of international law.

过去几年，各国提出了各种反措施合作建议。在本文中，我们要问的是，各国是否可以合法地合作对其他国家采取反措施，如果可以的话，在什么条件下可以合作。我们区分五种不同类型的协作：（1）独立但协调的行动； （二）借调； （三）共同行动； （四）援助和帮助； （5）我们所说的“代理反措施”——应另一国请求并代表另一国采取措施的想法。我们考虑每一种情况的允许性，无论是行为国本身有权采取反措施还是无权采取反措施。我们还提请注意与国际法发展相关的某些法律和政策考虑因素以及国际法发展的合理途径。