This paper analyzes a current issue of constitutional foundations for the harmonization of social interests in a public authority system. In particular, it observes the Russian Federation problems in this area. The matters of harmonization and sufficient fulfillment of people’s social interests within the public authority system require producing up-to-date means and methods of its formation and implementation. The current political modernization does not always have a tangible effect in accomplishing the state social functions; and the mechanism of proportional reflection of social groups’ interests within the modernization does not play the last role in this process. The state must have socialized institutions that reflect social expectations of a structurally inhomogeneous society to a sufficient extent to fulfill a social function.