I linje med partiet? : Maktspel och lojalitet i den svenska riksdagen

Sammanfattning: The preconditions for Swedish MPs’ (Members of Parliament) loyalty to their parliamentary party groups have been modified by two recent constitutional changes: the introduction of preference voting in the electoral system in 1998, and the 1997 reorganisation of the national budgetary process. The main purpose of this thesis is to determine the impact of these reforms on Swedish MPs’ inclination to defect from their party group’s interests. A theory is developed and its propositions empirically tested on the case of the Swedish Parliament. The theory states that the tasks of forming and upholding the party line are delegated from the party group to an elected leadership, and then re-delegated back to individual MPs. The party group leadership acts as a principal, monitoring the adherence of MPs as agents to party group interests in the fulfilment of these tasks. The nature of the interaction varies with the type of parliamentary activity, and the monitoring capacity of the leadership. This theory is strongly supported by Swedish data, and a comparative overview indicates that the theory may also be useful for analysing party loyalty in other parliamentary systems.The thesis uses a mixed methodology design, combining data from a survey study, an interview study, and a document study of Private Member Initiatives.The preference vote reform has increased MPs' willingness to defect, as well as actual defections from their party group’s interests. The effect is, however, mainly limited to electorally vulnerable MPs, who after the reform need to build a personal political profile. The budget reform has decreased defection on budgetary issues, but from a fairly low starting level. A third effect on party loyalty is found, in that the youngest generation MPs are significantly more prone to defect than their colleagues of older generations.