Two-and-a-Half-Party Systems and the Comparative Role of the `Half'

Abstract

In this article, the concept of the `two-and-a-half-party system' is re-examined, with particular focus on the role of the `half'. The analysis is on longer-term parliamentary democracies since 1945 or democratization. First, various ways of measuring a party system are outlined, and a new alternative is proposed. Based on this, 10 countries are seen to qualify (at least for certain time periods) as two-and-a-half-party systems: Australia, Austria, Belgium, Canada, Germany, Greece, Ireland, Portugal, Spain and the United Kingdom. Each of these systems is outlined and analysed. This category is then contrasted with both two-party systems and multiparty systems in order to explain its causes. Next, some general conclusions about when `half' parties are likely to matter more (in a governmental sense) are made, with a particular distinction occurring between `hinge' and `wing' half parties. Finally, the geographic shift in the presence of two-and-a-half-party systems is noted.