Groups can help solve problems where holdouts stymie multilateral cooperation – and groups can be especially popular where allies don’t have to share the benefits of their cooperation with others. Opting into groups won’t solve all of the problems inhabiting international economic coordination, however. Some kinds of problems need and require everyone to chip in, and the lowest amount of effort put forward by one person determines the benefits or welfare for everyone else.

UCLA economist Jack Hirsheifer explored this particular kind of problem in a series of famous papers, in which he explored under what circumstances public goods like safety and security would be voluntarily provided by private individuals. Among his many important observations, Hirsheifer found that a particular subset of problems are of such a nature that all relevant stakeholders have to cooperate in order to address them effectively. Moreover, in order to achieve optimal results, everyone who is affected by the problem has to cooperate at a high level to address it. If just one person slacks off, that person can rob the entire group of the benefits that their cooperation is supposed to make possible. It’s the Three Musketeers theory of economic cooperation: one for all, and all for one. Or else.