Doublemajorities

Doublemajorities is a voting rule in which a decision—often a constitutional amendment or major policy change—must obtain two separate majorities to be valid. Typically, one is a broad popular majority, and the second is a second dimension such as geographic regions, subnational units, or a second decision-making body. The aim is to ensure that reforms have wide support across different segments of the polity, not just a simple nationwide majority.

Common forms include two-stage thresholds that must be met together. In practice, this often means a nationwide majority of votes plus a majority of subnational units. The exact configuration varies by jurisdiction and context.

Australia provides a well-known example in constitutional referenda. A proposed amendment must win a majority of voters nationwide and also win a majority of states (the territories do not count toward the state majority). If either threshold fails, the amendment does not pass.

Switzerland employs a similar principle for constitutional amendments: not only a majority of voters nationwide but also a majority of cantons, with half-cantons counting as half. Both requirements must be satisfied for the amendment to take effect.

The European Union has used a form of double majority within its ordinary legislative procedure under the Lisbon framework: a decision typically requires the support of at least 55% of member states and at least 65% of the population. This structure ensures cross-country breadth and substantial demographic weight.

The rationale behind doublemajorities includes protection of regional or minority interests and the reinforcement of legitimacy for constitutional changes, though critics note potential rigidity and slower reform.