Given high costs of negotiating formal international institutions, states are widely expected to adapt, reform, and repurpose existing institutions rather than create new ones. Nevertheless, during the past century some 60 intergovernmental organizations (IGOs) have been directly replaced by a legal successor. Why do states sometimes dissolve an existing IGO only to replace it with a new one that takes over the incumbent organization’s mandate and assets—a practice known as institutional succession? We offer a theory of institutional succession and illustrate with examples. Against the dominant belief that creating new IGOs is a choice of last resort, we argue that reform and succession are equally expedient tools for achieving institutional change but address different negotiating hurdles. By creating a new institution (as opposed to amending an existing one) succession bypasses veto players that may stunt reform. However, succession suffers from potential diseconomies-of-scale (since not every member of an existing IGO may join the successor) which reform does not. Depending on which negotiation hurdle prevails, reform will be preferred to succession or vice versa. Our analysis advances existing understandings of institutional contestation and change within the life cycle of an international organisation.

鉴于正式国际机构的谈判成本高昂，人们普遍期望各国适应、改革现有机构并重新调整其用途，而不是创建新机构。然而，在过去的一个世纪里，大约有 60 个政府间组织 (IGO) 被合法的继承者直接取代。为什么国家有时会解散现有的政府间组织，然后用一个新的政府间组织取代它，接管现有组织的职责和资产——这种做法被称为机构继承？我们提供制度继承理论并举例说明。人们普遍认为，创建新的政府间组织是最后的选择，但我们认为，改革和继承同样是实现制度变革的权宜工具，但要解决不同的谈判障碍。通过创建一个新机构（而不是修改现有机构），继任者绕过了可能阻碍改革的否决者。然而，继任会面临潜在的规模不经济问题（因为并非现有政府间组织的每个成员都可以加入继任者），而改革却不会。根据谈判的障碍，改革优先于继承，反之亦然。我们的分析推进了对国际组织生命周期内制度竞争和变革的现有理解。