Polarizing Effect of Supermajoritarian Voting Rules

We identify a novel distortive effect of supermajoritarian voting rules such as qualified majority, filibuster or unanimity. Under such rules, different voters become pivotal under different  status quos. If policies are continuing in nature and a changing environment creates the need for renegotiation, legislators distort their voting behavior in favor of alternatives that make  them pivotal in the future. As a result, players disagree more often, and the policy is less responsive to the environment. We show that the voting distortions are bigger, the greater the supermajoritarian requirement. The distortions are also larger when the environment is volatile.  In the last decades, multiple U.S. states have passed constitutional amendmends that require a  qualified majority to increase taxes. Arguably, these amendments are designed to reduce spending and tax levels. Our results imply that such amendments can severely limit the states' ability to adjust taxation throughout the business cycle. We also show that they can even fail to achieve their primary goal of keeping taxes low.