The requirement of reciprocity is a very familiar idea. In its most basic form, it admonishes us to ‘do unto others as we would have them do unto us’. Accordingly, we should be willing to treat people kindly if that is how we would like them to treat us in return. But by the same token, if someone treats us unkindly, then reciprocity is often taken to mean that we should treat that person in like terms. Of course, this latter kind of reasoning can, and very often does, get people into all sorts of trouble. One thinks, for example, of the nuclear arms race or international trade wars, where threats of mutual destruction or financial embargoes determine the direction and character of international relations (Goodin 1992: 21–2). And naturally one also thinks of the countless examples of internecine, tit-for-tat retaliations between conflicting ethnic groups.

The requirement of reciprocity can therefore be understood as a force for good relations or as a force for bad relations. As a positive force, deliberative democrats have interpreted it to mean that since democratic decisions are mutually binding, citizens and representatives should aspire to a kind of political reasoning that is mutually justifiable (Gutmann and Thompson 1996: 53 and passim). More specifically, they should be prepared to justify their political proposals by providing reasons that others might reasonably be expected to accept (Rawls 1996, 1999; Habermas 1996, 1998b).