Chicken dilemma
Definition
Supporting definitions:
1. The A voters are the voters who prefer candidate A to everyone else. The B voters are the voters who prefer candidate B to everyone else. The C voters are the voters who prefer C to everyone else.
2. A particular voter votes sincerely if s/he doesn't falsify a preference, or fail to vote a felt preference that the balloting system in use would have allowed hir to vote in addition to the preferences that s/he actually votes.
Falsifying a preference means voting X over Y and not preferring X to Y.
Failing to vote a felt preference means preferring X to Y and not voting X over Y.
Premise:
1. There are 3 candidates: A, B, and C.
2. The A voters and the B voters, combined, add up to more than half of the voters in the election.
3. The A voters and the B voters all prefer both A and B to C.
4. The A voters are more numerous than the B voters. The C voters are more numerous than the A voters, and more numerous than the B voters.
5. Voting is sincere, except that the B voters refuse to vote A over anyone.
6. Candidate A would be the unique winner under sincere voting (...in other words, if the B voters voted sincerely, as do all the other voters).
7. The C voters are indifferent between A and B, and none of the C voters vote A or B over the other.
Requirement:
B doesn't win.
[end of CD definition]
In the chicken dilemma scenario described in the premise of the Chicken Dilemma Criterion (CD) defined above, if B won, then the B voters would have successfully taken advantage of the A voters' co-operativeness. The A voters wanted to vote both A and B over the candidates disliked by both the A voters and B voters. Thereby they helped {A,B} against worse candidates. But, with methods that fail CD, the message is "You help, you lose".
Some methods that pass the Chicken Dilemma Criterion:
ICT, Symmetrical ICT, MMPO, MDDTR, IRV, Benham's method, Woodall's method