In 1991, the Belgian government demissioned because of a dispute about armstrade to the Middle East between the french-speaking and the flemish parties of the majority. This was the result oft he agitation of pressure groups since the beginning of the seventies. They belong to the 'New Social Movements', motivated by post-material values. They developped a succesfull strategy to involve the 'old', pilarised pressure groups and the press. It proved that it was possible for non-pilarised pressure groups to influence the parliament and the government. Nevertheless, these pressure groups were only powerfull in Flanders, the northern part of Belgium. This made it possible for the linguistic cleavage to intervene in a decisive way in this political process. It broke up the consensus necessary for the maintaining of the government. The differences in the configuration of the New Social Movements between north and south will also be a reason for further steps in the process of federalising the Belgian state.