Dominant-party system

A dominant-party system, or one-party dominant system, is a political occurrence in which a single political party continuously dominates election results over running opposition groups or parties. Any ruling party staying in power for more than one consecutive term may be considered a dominant party (also referred to as a predominant or hegemonic party). Some dominant parties were called the natural governing party, given their length of time in power.

Dominant parties, and their domination of a state, develop out of one-sided electoral and party constellations within a multi-party system (particularly under presidential systems of governance), and as such differ from states under a one-party system, which are intricately organized around a specific party. Sometimes the term "de facto one-party state" is used to describe dominant-party systems which, unlike a one-party system, allows (at least nominally) democratic multiparty elections, but the existing practices or balance of political power effectively prevent the opposition from winning power, thus resembling a one-party state. Dominant-party systems differ from the political dynamics of other dominant multi-party constellations such as consociationalism, grand coalitions and two-party systems, which are characterized and sustained by narrow or balanced competition and cooperation.

In political literature, more than 130 dominant party systems between 1950 and 2017 were included in a list by A. A. Ostroverkhov. For example, in the post-Soviet states, researchers classify parties such as United Russia and Amanat (Kazakhstan) as dominant parties on the basis that these parties have long held the majority of seats in parliament (although they do not directly form the government or appoint officials to government positions). In Russian political science literature, such associations are often called "parties of power."

It is believed that a system with a dominant party can be either authoritarian or democratic. However, since there is no consensus in the global political science community on a set of mandatory features of democracy (for example, there is a point of view according to which the absence of alternation of power is, in principle, incompatible with democratic norms), it is difficult to separate the two types of one-party dominance.