Strategic Voting in Scandinavian Parliaments

Increasingly a case is being made that voting systems are highly manipulable —whether by strategic voting, agenda setting, or vote trading. Yet there exists little hard evidence on the actual extent of manipulation in real world settings¹ To a large degree this lack of evidence is a result of voting methods that allow only partial recovery of individual preferences over multiple alternatives and of a natural desire of legislators not to publicize misrepresentation of preferences or strategic agenda setting. Yet if we are to understand the empirical relevance of recent advances in the theory of voting, attempts must be made to apply new theoretical work to real world voting situations. In this paper we attempt to do this for voting in Scandinavian legislatures.
Our major concern is with effects of the order of voting on legislative proposals and with strategic voting that takes advantage of existing voting orders. Two distinct approaches are used. First, we present a detailed analysis of three situations in the Swedish parliament in which strategic voting was relevant. From these we conclude that when manipulation occurs in the Swedish context, it is not by altering the order of voting or by the creation of new, confounding alternatives, but by using strategic voting to take advantage of existing voting circumstances. Second, we take a more sweeping but less detailed look at voting in the Scandinavian legislatures. It appears from this analysis that the major way in which strategic voting is avoided is by limiting the number of alternatives to two.