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.
2. The "other candidates" are the candidates other than A and B.
3. 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.
Premise:
1. The A voters and the B voters, combined, add up to more than half of the voters in the election.
2. The A voters and the B voters all prefer both A and B to the other candidates.
3. The A voters are more numerous than are the B voters.
4. Voting is sincere, except that the B voters refuse to vote A over anyone.
5. 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).
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