Rethinking dominant party systems

Abstract: Empiricist definitions of ‘dominant party systems’ incorporating
‘longitudinal’ time requirements risk tautology and create unacceptable lags in
recognizing dominance. We urgently need an analytic definition that can identify
parties as dominant independently from their tenure of office. I suggest that a party can be recognized as dominant if three criteria are met simultaneously:
- The party is seen as exceptionally effective by voters, so that it is set apart
from all other parties.
- It consequently has an extensive ‘core’ or protected area of the ideological
space, within which no other party can compete effectively for voters’ support.
- At the basic minimum level of effectiveness that voters use to judge whether
to participate or not, the lead party has a wider potential appeal to more voters
than its rivals
This approach means that we can identify a party as dominant immediately it
establishes a higher level of effectiveness. It also generates some key hypotheses that
are well supported in the existing literature on dominant party systems and could be
more precisely tested in future, specifically:
- Factionalism should be a more serious problem for dominant party leaders
than in more competitive systems.
- In ‘uncrowded’ ideological space one-party dominance will be sustained by
the strong logic of opposition parties adopting ‘clear water’ positional
strategies.
- Only when some opposition parties adopt ‘convergent’ or ‘deeply convergent’
positioning strategies will support for dominant parties tend to be seriously
eroded.
- Factional exits from the dominant party are the most likely route by which
opposition parties with ‘deeply convergent’ strategies emerge.
- Greater crowding of the ideological space is a key stimulus to some opposition
parties adopting convergent or deeply convergent strategies. It also helps
overcome the positional advantages that dominant parties often have, making
minimum connected winning coalitions easier for opposition parties.
- Hence the multiplication of parties is a key dynamic undermining dominant
party systems.
In political science an idea often emerges inductively and becomes widely adopted before ever an intellectually adequate specification of it has been provided. Such a concept is that of a ‘dominant party system’ (Arian and Barnes, 1974). ‘Longitudinal’ versions of the concept are tautological and re-descriptive – they say only that a party is dominant when it is continuously in government for a specified period. As a result the term is briefly cited in around half of the specialist dictionaries or encyclopaedias in political science but ignored in the remainder of the definitional volumes and almost never recognized as useful even in directly adjacent fields, such as the analysis of electoral systems. This paper sets out to re-conceptualize dominant party systems in a different, more analytic way, using a public choice-based approach. I first briefly survey current problems and then propose a new definition making no reference to
tenure of office. The second section applies this approach to the existing literature on the dynamics of dominant party systems. I conclude with a set of hypotheses that should prove helpful in guiding future empirical research.