In a context of a process of hollowing of the state whereby parties are less and less rooted in society, this paper tests two models of constitutional regulation of parties and pressure groups in Europe. The aim is to disentangle their complementarity or rivalry in performing democratic functions in a political system. Bridging constitutionalism, party organization and representation theories the paper investigates major functions assigned to both types of organizations and analyses the way they are regulated in constitutions. The paper arrives at European patterns of constitutional regulation which also take into account the institutional aspects of European political systems.
