SODA voting (Simple Optionally-Delegated Approval): Difference between revisions

# Before the election, all candidates must rank the other candidates (including declared write-ins) in order of preference. Equal rankings and truncation are allowed. The candidate's rankings are all made public. Later, in the "delegation" step, any delegation from one candidate must be consistent with that candidate's rankings. This helps reduce the possibility of corrupt vote-selling or "smoke filled rooms".

# Each voter submits an approval ballot. There is some way (such as an extra write-in slot) to vote for an invalid candidate named "do not delegate".

# Any "bullet vote" - that is, a ballot which votes for only one candidate - is considered a "delegable vote" for a candidate. These votes are tallied for each candidate. Of course, any ballots which vote for "do not delegate" or any other invalid write-in are not considered as bullet votes.

# Approval totals for each candidate are also tallied. These preliminary results are announced, along with the number of "delegable votes" each candidate has.

# If any candidate has an absolute majority at this point, or cannot possibly be beaten by any other candidate using the delegable votes and candidate rankings available, then they win immediately.

# There is a brief period - perhaps a week - for candidates to analyse and negotiate based on these preliminary results. (Actually, the correct strategies for all candidates and the resulting winner will already be obvious. Usually, all candidates except this winner would concede as soon as preliminary results are announced. However, for the occasional candidate inclined to act irrationally in a way that matters - say, by not delegating to an ally, even though the alternative is to see an enemy elected - this interim period would give them a chance to rethink things and come into reason.)

# All candidates, in descending order of the number of delegable votes they have, publicly delegate their votes; that is, they choose a number N, and their "delegable vote" total is added to the approval totals of their top N favorites as announced in step one. They may choose N=0 - that is, not delegate their vote to anyone. They may not choose N=(number of candidates) - that is, delegate their votes to everyone. If they declared a tie in their preferences, they must either delegate to all candidates whom they included in that tie (as well as anyone they ranked above that), or none of them. (Note: Doing this in descending order prevents a weaker candidate from making an ultimatum to a stronger candidate, and thus strengthens the strategic equilibrium of any pairwise champion there is.)

# The highest total wins.