The Belgian "Rrainbow coalition": Optical illusion or mechanical phenomenon?

Introduction In July 1999, the formation of a Liberal-Socialist-Green government, consisting of six parties (the Flemish and the French-speaking parties of each of these three ‘party families’) under the first Liberal Prime Minister since World War II, is a puzzling outcome both for classical coalition theories and for traditional Belgian politics. This coalition was oversized, unconnected on the left-right dimension and therefore not a minimal policy range coalition either; it excluded the median Christian Democratic party, which had participated in all governments since 1958; and it included the Greens, who had never been included in any national executive (see Dumont and Bäck 2006). In addition, even though the outcome was unexpected, the process that led to it did not involve the testing of other formulas and a new government was in place after less than a month in a country that is famous for the length of its coalition negotiations (Müller and Strøm 2000; De Winter and Dumont 2008). What is to be explained in the following sections, however, is the outcome of these negotiations: in particular, why Liberals and Socialists, who had refused to govern together for a very long time because of their divergent positions on socio-economic issues, came to terms in order to exclude the Christian Democrats, and how and why the Greens were invited to join this already unexpected coalition.