National Party Division and Divisive State Primaries in U.S. Presidential Elections, 1948–2012

In presidential nomination campaigns, individual state primaries and a national competition take place simultaneously. The relationship between divisive state primaries and general election outcomes is substantially different in presidential campaigns than in single-state campaigns. To capture the full impact of divisiveness in presidential campaigns, one must estimate both the impact of national party division (NPD) and the impact of divisive primaries in individual states. To do so, we develop a comprehensive model of state outcomes in presidential campaigns that incorporates both state-level and national-level controls. We also examine and compare several measures of NPD and several measures of divisive state primaries found in previous research. We find that both NPD and divisive state primaries have independent and significant influence on state-level general election outcomes, with the former having a greater and more widespread impact on the national results. The findings are not artifacts of statistical techniques, timeframes or operational definitions. The results are consistent—varying very little across a wide range of methods and specifications.