ABSTRACT
All collective security arrangements have certain rules. States identify each other as fellow citizens within a larger society, they agree to follow a particular set of rules, and they enforce those rules through multilateral action, including the use of force if necessary. Beyond this basic structure, however, many forms of collective security are possible, varying by the substance of the rules, who determines the rules, and how to enforce the rules. Collective security is a slippery concept, and this chapter delves into its complexities.
