Size, Party Systems andStability.

Earlier studies have demonstrated that party system fragmentation rises with increasing country size, and that government stability declines with increasing party system fragmentation. This paper tests the assumption that the effects of fragmentation on stability are conditioned by size. The theoretical expectation is as follows: 1) There is a leveling-off of the effects of increasing size on the fragmentation of party systems. A country with ten million inhabitants may have ten parties in the parliament, but one would not expect a country with a hundred million inhabitants to have a hundred parties in parliament. Most electoral systems would prevent this, and the voters normally prefer not to waste their votes on chanceless parties. 2) In consequence, parties in larger countries contain a wider spectrum of preferences than parties in smaller states, all other things being equal. This, in turn makes for weaker governments in larger countries. Parties will, due to their internal heterogeineity, be less dependable as coalition partners in large than in small states. Consequently, the effects of party system fragmentation on stability should be stronger in larger states. The paper tests these hypotheses statistically in all democratic states with a parliamentary or semi-presidential form of government. The data originate from a panel data set covering the period 1960-2001 (N=350). [ABSTRACT FROM AUTHOR]