The Rule, Not the Exception: One-Party Monopolies in the American States

Abstract Thousands of studies have examined party competition in the American states, finding significant consequences for voter turnout, policy adoptions, and more. Long-term patterns control received less attention. Here, we reexamine operationalization competition. We then update Klarner’s state partisan balance data to include house senate composition gubernatorial vote share since 1930s, adding—in light nationalization politics—presidential proportion Democrats each state’s congressional delegation. After establishing a threshold one-party dominance, examine frequency duration subnational monopolies, highlighting regional variations relationship between national measures applying index turnout. Our analysis reveals that extended periods dominance – currently on uptick are rule, not exception, states phenomenon ripe further exploration.