A project in Political Philosophy, utilizing Experimental Economics. Aimed at understanding and predicting international cooperation between states, and outlining the conditions under which international cooperation between states is made more and less likely. In order to model states as potential cooperators, we must understand whether and to what extent states possess the agency necessary to cooperative action. The first task of this project will be to investigate the largest group of persons possessing collective agency within the legal / political territory of the state. We generally talk as though the state is something of which we are members; I hope to be able to accommodate our ordinary talk by locating agency in a collective at least roughly similar to what we think of as 'the state'. In the best case, this will be the maximal group of those meeting a certain criterion, for example possessing citizenship or residency, identifying as a national of that state, being regularly engaged in voting and paying taxes. In the worst case, this will be the minimal group of those meeting a more restrictive condition, for example holding an official role within the executive of the state, or occupying the position of Head of State. Once it has been established where exactly agency lies in the group we commonly refer to as 'the state', it will be possible to start thinking about cooperative interactions between such agents, and to start theorizing about states responsibilities in the context of these cooperative interactions, and their members' roles and responsibilities as the constituents of states in these cooperative interactions. This will involve delineating what states' obligations mean for members (citizens, nationals), which is to say, what the 'translation' is between a large-scale collective obligation and the individual constituents' obligations which together comprise it. The project will shed new light on individuals' obligations as members of the state.