Most democracies see only a limited role for supermajorities

WHEN THE Polish-Lithuanian commonwealth was dismembered by the Habsburg Empire, Prussia and Russia in 1795, it was in part because its parliament, the Sejm, had spent most of a century getting very little done. A 17th-century rule known as liberum veto allowed any individual delegate to end a parliamentary session and scuttle all the bills it had passed with a simple cry of “Nie pozwalam!” (I do not allow it). It was not a recipe for progress.