The need for and adoption of certain social policies for the nation are frequently rationalized by their advocates as being in the public interest. Often, though, the interest of the many merely disguises the special interests and wants of the few. It is obvious that the social choices made in the policy process only rarely benefit the interests of all without being adversely consequential to some. This paper argues that the problem of social choice in the conflictual process of policy making is as much a conceptual dilemma as a practical political or economic one. A major source of this confusion derives from the lack of a consensually valid conceptualization of the public interest-how it is defined, measured, advanced and operationalized in public policy. An analytical framework is used to define and assess the nature of the public interest and the conditions which must prevail if any social policy can be said to be in the public interest.