In recent decades, swing voters in courts and legislatures have made many of the United States’ most important decisions of law and policy. It would be easy to conclude from the recent history of the Supreme Court and Congress that democracy or majority rule inevitably entails placing many of a society’s most important decisions in the hands of swing voters. Far from being inevitable, however, swing voters result from a highly contingent set of circumstances, both ideological and institutional.

This Article probes these contingencies, describing and evaluating swing voters and the power they hold. It first explains the conditions under which swing voters will exist and wield power, including an account of why swing voters hold greater power than other pivotal voters. Understanding swing voters requires understanding institutional design and internal procedures: some arrangements increase swing voter prevalence and power, while others have the opposite effect. The ways in which rules construct swing voters give institutional designers and reformers ample tools at their disposal to increase or decrease the prevalence of swing voters and the extent of their power. But nearly any judgment about swing voters and the power they exercise necessarily rests on thorny empirical and normative issues—including the relative importance of moderation and stability in different institutions, the performance of swing voters as compared to other voters, and how swing voter power interacts with principles of majority rule. Swing voters are therefore best understood not as ends unto themselves, but as windows into broader issues in democratic theory and institutional design.

Jonathan S. Gould