Liberalism, in its different forms, takes into account some positive but limited requirements of mutual assistance which, in a democratic society, are institutionalized and implemented by laws. This requirement of impartiality has been implemented by the increase of public functions of mutual assistance, by the development of the welfare State and by the social democratic alternative of liberal theory. However and although the liberal State tends towards a conciliation of the requirements of impartiality and of the requirements of individuality, it remains unsatisfactory. Liberal societies impose a limited impartiality, obtained by means of institutions which require of their members a specific attachment to certain rights and to certain procedures. This task is indeed easier to implement than the institutionalization of a more levelling system. However we would like to determine up to which point and in which conditions it is possible to establish rights to a social minimum in addition to the rights to fundamental liberties and to legal and political equality guaranteed to all. From there, it would be possible to constitutionalize the elimination of poverty, through a set of limited dispositions that the legislative and executive authorities would be legally charged to implement, through specific programmes. If these measures can escape from political bargaining and from interested calculations, a first step towards a more global socio-economic equality would be made. Thus we would like, in the following developments, to consider the conditions of a social and political system, which satisfy the requirements of impartiality more than liberalism does, even in its more equalitarian versions. In the same way, we would like to specify the means of a progressive institutionalization of socio-economic equality.