Political parties are at the centre of democratic and parliamentary systems. The current classic political parties are expressions of societal cleavages of the nineteenth and twentieth century. After the Second World War, those parties look for new strategies to assure important parts of the electorate. One of the strategies is to integrate the existent cleavages into the party itself. But this kind of integration is not without ideological and organisational consequences. These cleavages manifest themselves within the party as subgroups and have to respect some overarching loyalties. As far as the internal decision making process is concerned, they have some consequences as well. Rules of pacification have to be respected when the integration of cleavages has to be recognizable and successful. The disadvantage of these rules of pacification is the absence of a formal active involvement of the party on the ground. At the same time, the presence of subgroups can lead to realdemocratic involvement and even discourage oligarchie tendencies.