The Vote-Left Equilibrium: A Deterministic Coordination Strategy for the Faithful in The Traitors
For players of The Traitors, this provides a practical coordination strategy that significantly improves winning odds against colluding Traitors.
The paper introduces the Vote-Left protocol for the social deduction game The Traitors, a deterministic voting rule that makes deviations immediately identifiable. Under full compliance, it achieves the same banishment distribution as random voting, and combined with a punishment rule, it constitutes a Perfect Bayesian Equilibrium for most game states, raising the Faithful's winning probability by approximately threefold over random voting under collusion.
The Traitors is a social deduction game in which an informed minority of Traitors face an uninformed majority of Faithful, and the recurring question facing the Faithful is how to vote. Random voting is known to be optimal for the uninformed majority under simultaneous-signal protocols [Braverman, Etesami and Mossel, 2008], but when votes are cast individually, random votes are indistinguishable from strategic ones and the Faithful remain exposed to coordinated Traitor collusion. We introduce the Vote-Left protocol, a deterministic rule under which every player votes for the next surviving player in a fixed cyclic ordering. Under full compliance every surviving player receives exactly one vote, so the banishment distribution coincides with random voting; since prescribed votes are deterministic functions of public information, any deviation is immediately identifiable. Combined with a simple punishment rule, Vote-Left constitutes a Perfect Bayesian Equilibrium for every state with $n_t > 2m_t + 2$, a region that contains every televised configuration. We characterise the Traitors' best response in the late-game phase ($n_t \leq 2m_t + 2$): deviate via collusion once the Faithful no longer have enough votes to guarantee punishment. Across the configurations played on television, Vote-Left raises the Faithful's winning probability by a factor of approximately three over random voting under collusion.