Multi-party system

In political science, a multi-party system is a political system where more than two meaningfully distinct political parties regularly run for office and win offices (eg, membership in parliament) in elections.^[1] Multi-party systems tend to be more common in countries or jurisdictions (together, 'polities') which use proportional representation forms of election, compared to those that have implemented winner-take-all elections; this tendency is known as Duverger's law.

In multi-party countries or polities, usually no single party achieves at an election a parliamentary majority on its own (elections result in what are sometimes called hung parliaments). Instead, to craft a majority, multiple political parties must negotiate to form a coalition (also known as a 'minority government') which can command a majority of the votes in the relevant legislative organ of state (eg, parliamentary chamber). This majority is required in order to make laws, form an executive government, or conduct basically any of the necessary work of the parliament or the government (eg, to choose a president, elect parliamentary leadership, adopt a legislative agenda, or change rules of parliamentary procedure).

This tendency to not give sufficient power to one party to alone make significant changes—at least not without the support of other parties elected—tends to moderate governmental decision making in multi-party system jurisdictions; generally, it encourages negotiation over ideological purity, and more centrist, cooperative and compromising parties, governments and policies.

^ Education 2020 definition of multiparty: "A system in which several major and many lesser parties exist, seriously compete for, and actually win public offices."

[1] Education 2020 definition of multiparty: "A system in which several major and many lesser parties exist, seriously compete for, and actually win public offices."

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