How could one Sejm deputy use the liberum veto to block legislation?

In the Polish-Lithuanian Commonwealth, the liberum veto was a constitutional principle rooted in the belief that all members of the nobility were politically equal and that legislation required unanimous consent.12

A single deputy could block legislation or paralyze the government through the following methods:

• Individual Veto: If a deputy believed a measure was harmful to his constituency, he could exclaim "Nie pozwalam!" ("I disapprove!"). This single negative vote immediately nullified the measure, regardless of the support from other members.23
• Dissolution of the Sejm: A deputy could use his individual veto to dissolve the entire session of the Sejm. This action not only halted current proceedings but also nullified all acts previously passed during that session, requiring them to be resubmitted to a future Sejm.12

While originally intended as a safeguard against tyranny and a protection of local interests, the practice was frequently exploited by magnates or foreign powers—who often bribed deputies—to obstruct government functions and prevent the centralization of power.123