We derive the equilibrium institutional design of representative democracy by citizens who first vote on the supermajority required for a new policy to be adopted, and then delegate decision making to a legislature that selects policy given that institutional constraint. A legislature that can freely tailor policy to reflect society’s current preferences is good. However, the views of the median legislator or agenda setter may differ from the median citizen’s, and an unchecked legislature can implement bad policy. We characterize how the primitives describing the preferences of actors and the status quo policy affect the equilibrium degree of legislative flexibility