Coalition voting

Steven J. Brams, Peter C. Fishburn

    Research output: Contribution to journalArticlepeer-review


    Coalition voting (CV) is a voting procedure for electing a parliament and choosing a governing coalition under a party-list system of proportional representation. Voters have two different kinds of votes. The first kind is a "party vote," which is divided evenly among all parties of which the voter approves. These fractional approval votes determine the seat shares of parties in the parliament. The second kind of vote is a "coalition vote," which counts for all majority coalitions that are acceptable because they include all parties that the voter designates Y ("yes") and exclude all parties that the voter designates N ("no"). The majority coalition acceptable to the most voters and that has no superfluous parties becomes governing, provided that the parties it comprises agree. By placing a premium on precisely the most approved majority coalitions, CV encourages parties, before an election, to reconcile their differences and form coalitions that are likely to have broad appeal. Such coalitions, insofar as they formulate coherent policies, facilitate voter choices, producing a convergence of voter and party/coalition interests. Theoretical properties of CV are analyzed, and optimal strategies of voters and parties are investigated. CV's most likely empirical effects in faction-ridden multi-party systems, like those of Israel and Italy, are discussed. Finally, the practicality of CV as an election reform is considered, and some possible modifications are mentioned.

    Original languageEnglish (US)
    Pages (from-to)15-26
    Number of pages12
    JournalMathematical and Computer Modelling
    Issue number8-9
    StatePublished - 1992

    ASJC Scopus subject areas

    • Modeling and Simulation
    • Computer Science Applications


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