Societies and smaller groups throughout history have formed organizations that provide and sustain them with security, access to resources, social rules, and means of continuity. Frequently they also devised, embodied, or sought more ephemeral objectives or qualities such as identity, glory, renown, and reputation. The institutional forms they have taken have varied greatly. Even terms we commonly use to designate polities – tribes, clans, empires, principalities, city-states, protectorates, sultanates, or duchies – would not begin to cover the actual diversity of political forms.

In contemporary parlance, all these actors are “polities” (Ferguson and Mansbach, 1996) in the sense that they have distinct identities, authority structures, and leadership. Such types of polities have probably numbered in the hundreds of thousands throughout recorded history. But most did not survive their leaders' lives, while a few have had a continuous organized history, in the case of the Roman church, of almost two millennia.

Our concern, however, is with states, the only contemporary political organizations that enjoy a unique legal status – sovereignty – and that, unlike other types of polities, have created and modified enduring public international institutions. They are thereby the foundational actors of international relations. Other types of polities may ultimately become states but until they have transformed themselves into public bodies – moral agents representing some sort of community – they do not have the legal standing of states.