The rule that a decision is ratified only if every single voter supports it. The jury rule for conviction, in some legal systems, is a unanimity rule. Famous historical examples were the procedures to elect the king of Poland in the eighteenth century, and the Pope prior to the Third Lateran Council of 1179 which substituted a two‐thirds majority rule (see qualified majority rule). The unanimity rule gives each and every voter a veto over the outcome. Therefore, if any voter has corrupt or ulterior motives, they may have to be paid off. Contemporary observers thought that the Polish monarchy was weak for this reason; an outside power such as Russia or Austria need only bribe one Polish nobleman each to prevent any king from being chosen.
Subjects: International Law — Politics.