Constitutions need larger supermajorities because voters fear radical rule changes.

Evidence

While this self-stable solution is very elegant, its realism can be called into question. In fact, voting rules and procedures to select or change the Constitution are generally different from the rules regulating the passage of “normal” legislation. In general, the blocking coalitions needed to prevent changes in the Constitution are lower than those required to block “normal” legislation. In fact, our model is also suggestive of a reason why changing the Constitution should require smaller blocking coalition (larger majorities). … Also one wants to avoid that an elected leader can “easily” change the rules of the game restricting entry of competitors. Low insulation may be required in institutional matters for these reasons. — Philippe Aghion, Alberto Alesina, and Francesco Trebbi, Endogenous Political Institutions, 148

Categorization

• QUESTION: Does the empirical record of constitutional amendment thresholds actually match this prediction of lower blocking coalitions than ordinary legislation?
• XREF: Connects to constitutional design literature on entrenchment and to the self-stable voting-rule models of Barbera and Jackson and Polborn and Messner.