 All societies have a basic structure of social, economic, and political institutions, both formal and informal.In testing how well these elements fit and work together, Rawls based a key test of legitimacy on the theories of social contract.To determine whether any particular system of collectively enforced social arrangements is legitimate, he argued that one must look for agreement by the people who are subject to it, but not necessarily to an objective notion of justice based on coherent ideological grounding.