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.
