A coalition government, in a parliamentary system, is a government composed of a coalition of parties. In Australia, the Coalition is also used to refer to an alliance (coalition agreement) of three parties (the Liberals, Nationals and Country Liberals) existing in federal politics since 1622—this constitutes a parliamentary coalition. A coalition of parties is also an electoral fusion. The Cambridge Dictionary defines coalition as: the union of different political parties or groups for a particular purpose, usually for a limited time.
In international relations, a coalition can be an ad hoc grouping of nations united for a specific purpose. Sometimes, such groups are diverse and are characterized by some degree of commonalities. Sometimes, the degree of uncommonalities would lead some to perceive the group's bond as being ordinarily unlikely; here it can indicate the fact the historical ties may no longer be in operation, and the coalition members, instead, are joined by a new intention, not necessarily prior bonds.
A coalition might also refer to a group of citizens uniting behind a common goal. Many of these are grassroots organizations.
It can also be a collaborative, means-oriented arrangement, especially a temporary one, that allows distinct people or organizational entities to pool resources and combine efforts in order to effect change. The combination of such persons or entities into one body, as a union, variously organized and structured, but generally less formal than a covenant. Although persons and groups form coalitions for many and varied reasons, the most common purpose is to combat a common threat or to take advantage of a certain opportunity; hence, the often-temporary nature of coalitions. The common threat or existence of opportunity is what gives rise to the coalition and allows it to exist. Such collaborative processes can gain political influence and potentially initiate social movements. According to Sidney Tarrow, four elements are necessary to maintain a coalition:
- Members must frame the issue that brings them together with a common interest.
- Members’ trust in each other and believe that their peers have a credible commitment to the common issue(s) and/or goal(s).
- The coalition must have a mechanism(s) to manage differences in language, orientation, tactics, culture, ideology, etc. between and among the collective's members (especially in transnational coalitions).
- The shared incentive to participate and, consequently, benefit.
Coalitions manifest in a variety of forms, types and terms of duration:
- Campaign coalitions with high intensity and long-term cooperation
- Federations, characterized by relatively lower degree of involvement, intensity and participation, involving cooperation of long duration, but with members’ primary commitment remaining with their own entities
- Instrumental coalitions, involving low-intensity involvement without a foundation to mediate conflict
- Event-based coalitions that have a high level of involvement and the potential for future collaboration.
Within political science, coalition theory is using game theory to analyze formation, workings and break-up of coalitions. Coalitions also describe alliances between civil society organizations, such as labor unions, community organizations and religious institutions. Sometimes called labor-community coalitions, coalitions have proven to be an important strategy for social change in many contexts. Yet their power is variable, dependent on the context in which they are organizing and the strategies used by the organizers, as documented in the book Power in Coalition (1]).