Venice defeated election corruption with a 10-stage lottery-vote hybrid

By the 13th century, Venice needed a reliable way to select its Doge, the republic's head of state, from among its aristocratic families, in a political environment where rival factions had the wealth and motive to buy or coerce a favorable outcome. A straightforward election among the aristocracy invited vote-buying and domination by whichever faction had the most money or influence; a straightforward lottery avoided that risk but ignored competence and legitimacy entirely, since a purely random draw could hand power to someone with no support or ability.

Any selection method that used a fixed, predictable path from candidacy to office also created a specific target: factions with enough resources could identify in advance exactly who would hold decisive voting power at each stage and focus their bribery or coercion precisely there.

Starting in 1268 and continuing until the end of the Republic in 1797, Venice selected its Doge through ten alternating rounds of random lottery and committee approval voting: thirty Great Council members were chosen by lot, reduced by lot to nine, who nominated forty candidates each requiring individual approval votes, reduced by lot to twelve, who nominated twenty-five, reduced by lot to nine, who nominated forty-five, reduced by lot to eleven, who elected the final forty-one electors, sequestered until they chose the Doge by a supermajority of at least twenty-five votes.

Alternated lottery and approval voting across ten stages, so no one could predict who would hold decisive power to corrupt, while approval still filtered for legitimacy.

Random draws at each stage made the composition of future voting bodies unpredictable.

No faction could identify in advance which individuals would hold decisive power.

The cost of corruption rose because influencing everyone possible was impractical.

Interleaved approval votes still filtered for candidates with broad support.

When a process is valuable enough to attract manipulation, make the decisive power unpredictable by interleaving random selection with deliberative approval at each step.

Because no faction could know far enough in advance which specific individuals would hold decisive power at any given stage, the protocol made concentrated bribery or coercion of the election impractical, while the repeated committee-approval steps still filtered for candidates with broad support rather than leaving the outcome purely to chance.