Who's Dominant?: Incumbent Longevity in Multiparty Regimes, 1950-2006

Abstract

In dominant party systems, a single party or coalition continuously controls the national executive by winning contested elections over an extraordinary period of time. Studies of dominant party systems have proliferated in recent years, but cross-national research on this topic has been hindered by inconsistent definitions of dominance, a focus only on “successful,” long-lasting cases to the neglect of shorter-lived ruling parties, and a “small-N” problem that precludes probabilistic inference. In this paper I describe an original dataset of ruling party duration in all electoral autocracies and democracies that existed between 1950 and 2006. I use this data to identify more than 40 dominant party systems that occurred during this period. I find that the large majority of long-lived ruling parties were “first-movers” in the party system — they either founded the competitive regime or won the first elections, then retained power for several successive elections. A comparison of survival rates and median ruling party durations for both first-mover and non-first-mover parties shows that the median first-mover party lasts about twice as long. However, there is also enormous variation in first-mover duration — party origins by themselves do not explain why some initial incumbents endure much longer in power than others. The findings hold two important implications for large-N research on dominance: (1) most dominant parties are former monopolists who have done well at retaining market share, so the rate of decay of these initial advantages is a better way to operationalize the dependent variable, and (2) the comparison set for testing explanations of dominance should include all first-mover parties in electorally-contested regimes, rather than all ruling parties or only the most long-lived ones.

Keywords: dominance, dominant party system, democratization, opposition development