A Behavioral Theory of Electoral Structure

Why are party systems in modern democracies so essentially robust? We theorize patterns of electoral competition as the outcome of a struggle between entropy and structure. Forces of entropy entail idiosyncratic voting behavior guided by subjective evaluations, while forces of structure entail coordinated behavior emerging from objective aspects of party preference. Our model locates determinants of party preference on a continuum spanning subjective and objective concerns. Entropy is endemic but elections for nationwide executive office periodically prime objective concerns, reinstating structure in party systems. We demonstrate the cyclical pulse of national elections in a comparative analysis of pseudo-randomized survey data from the European Election Studies since 1989. We also show how feedback from differently-sized party systems consolidates different working equilibria.