Article révisé par les pairs
Résumé : Confronted to the shrinkage of their traditional worker electorate, European social democrat parties have aimed to enlarge their electoral base to the intermediary salaried classes. This strategy submits these parties to a permanent dilemma since the intermediate and the working classes hold very different ideological and political views. These gaps between social classes inside the parties are reinforced by huge gaps between territories. We will show for the Belgian case that the electoral base of social democrat parties is very heterogeneous in ideological terms, because of its social and territorial diversity. We will finally state the hypothesis that the social supervision related to the parties enables them to cope with this dilemma with different results.