Why elites sometimes undo their own constitutional privileges

Most new democracies begin operating under an authoritarian constitution from the past that favors elites connected to the previous era. While these constitutions are designed to be difficult to change, important changes nonetheless sometimes occur, occasionally at the behest of the very elites that these constitutions were meant to protect and favor. Why do elites support these changes? We develop a dynamic imperfect information bandwagoning model of reform to explain shifts in elite-biased constitutions. Unanticipated shocks can make constitutional changes overwhelmingly popular, encouraging moderate constitutional opponents and supporters to join a radical opposition in voting for reform. This encourages a president who supports the status quo to join the bandwagon by refraining from vetoing the reform, attempting to gain concessions in the meantime. We demonstrate the utility of the model in the context of reforms to the Chilean pension system in 2021.