Liberum veto

A parliamentary rule in the Polish–Lithuanian Commonwealth that let any deputy block legislation and dissolve a session of the Sejm. It turned the assembly’s requirement for unanimity into a source of political paralysis.

Sejm: The principal parliament of the Polish–Lithuanian Commonwealth, composed of the king, Senate, and Chamber of Deputies. The liberum veto operated in the Sejm’s Chamber of Deputies.
Polish–Lithuanian Commonwealth: A federated state joining the Kingdom of Poland and Grand Duchy of Lithuania from 1569 to 1795. The liberum veto belonged to this state’s parliamentary system.
Saxon Era in Poland: The period of Polish history under the Wettin kings Augustus II and Augustus III, from 1697 to 1763. Repeated disruptions of the Sejm made the veto especially notorious during this period.
Majority rule: A decision rule under which a proposal passes when it receives more than half of the votes cast. Majority voting allowed legislation to proceed without every deputy’s consent.
Unanimity: A decision rule requiring every participant to agree for a proposal to pass. The veto arose from treating unanimous consent as necessary for Sejm legislation.
Noble democracy: The political system in which the nobility of the Polish–Lithuanian Commonwealth exercised extensive rights and power. The veto reflected the political ideal that each noble deputy held equal standing.
Augustus III of Poland: King of Poland and Grand Duke of Lithuania from 1733 to 1763, and Elector of Saxony as Frederick Augustus II. No ordinary Sejm completed its legislative work during his reign.
Confederation (Polish–Lithuanian law): A political association in the Polish–Lithuanian Commonwealth whose members could bind themselves to act collectively. Confederations could make decisions by majority and suspend the ordinary veto rule.
Parliamentary procedure: Rules governing debate, decision-making, and conduct in a legislative assembly. The veto was a procedural rule whose reach depended on how sessions were conducted.
Golden Liberty: The body of political rights and privileges held by the nobility of the Polish–Lithuanian Commonwealth. The veto was defended as an expression of noble political liberty.

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