Proposed Statutory Rules for DMC
This page is intended to specify the proposed statutory rules for Definite Majority Choice in a form suitable for use by legislatures or in referenda or initiatives. The properties, criteria satisfied and motivations for DMC should be discussed elsewhere.
Each ballot shall list all qualified candidates for the office, and the voter shall be allowed to write in any reasonable number of other candidates. On the ballot, the voter shall be allowed to rank candidates in order of preference, and a sufficient number of ranks shall be made available so that the voter may express separate rank for each qualified and write-in candidate. Ranking one candidate higher than another shall be considered equivalent to a vote cast for the higher-ranked candidate against the other in the pairwise, or one-on-one, contest between those two candidates. A voter also may give the same rank to more than one candidate, or leave some candidates unranked. When a voter ranks two or more candidates equally, the voter shall be assumed to be casting no vote in the pairwise contest between any two of those candidates. When a voter does not rank all candidates, it shall be assumed that this voter is casting a vote for each ranked candidate against each unranked candidate in their respective pairwise contests, and that this voter is casting no vote in any pairwise contest between any two unranked candidates.
The ballot shall allow a voter to specify an approval cut-off, either by ranking candidates above a predetermined rank or as a separate Disapproved option on the ballot, in order to indicate that all candidates above the approval cut-off are to be considered approved, and all candidates at or below the approval cut-off are to be considered disapproved. The number of separate ranks available shall be sufficient to rank all qualified and write-in candidates at separate rank entirely above or entirely below the approval cut-off. If a voter ranks no candidates at or below the approval cut-off, all ranked candidates shall be considered approved. Ranking a candidate higher than the approval cut-off shall be considered equivalent to casting an approval vote for the candidate. The approval rating of a candidate is the total number of valid ballots on which that candidate is ranked above the approval cut-off.
- A majority winner is a qualified or write-in candidate such that on a majority of the valid ballots this candidate is ranked above every other qualified or write-in candidate. If there is a majority winner, then that candidate wins the election.
- Suppose that there is no majority winner. Then a qualified or write-in candidate X is called undefeated when, for every other qualified or write-in candidate Y, X defeats Y in their pairwise contest. If there is an undefeated candidate, then that candidate wins the election. The majority winner, if it exists, will always be undefeated.
- Suppose there is no majority winner and no undefeated candidate. A candidate is definitively defeated if that candidate suffers a pairwise defeat from any other higher-approved candidate. When no undefeated candidate exists, the least-approved candidate must therefore be definitively defeated. The Definitive Majority Choice winner is that candidate who, after elimination of zero or more least-approved candidates, is undefeated against all remaining candidates. While there is no Definitive Majority Choice winner, the least-approved remaining candidate is eliminated from the race. As soon as a Definitive Majority Choice winner is created, that candidate wins the election. The majority winner or the undefeated candidate, if either exists, will also always be the Definitive Majority Choice winner.