Selecting For Extremists: Evaluating the Impact of Judicial Selection Methods on Ideology

U.S. states display striking heterogeneity in their choices of judicial selection method. Researchers have produced dozens of papers exploring how the most commonly-used selection methods—partisan election, nonpartisan election, merit selection, and unconstrained gubernatorial appointment—affect the ideology and behavior of the judges they produce. Nevertheless, these articles have studied only a limited set of outcome variables. Most published work concerns either how selection method affects (1) judicial responsiveness to public opinion or (2) ideological direction. To my knowledge, however, no empirical work explores how choice of selection method impacts ideological extremity. This paper fills that gap. Using generalized propensity score matching, fixed effects counterfactual estimators, and synthetic controls to conduct causal inference, I examine whether some methods of selection produce more moderate (or extreme) judges than others. I find consistent evidence that judges picked by unconstrained gubernatorial appointment are more extreme on average than those selected by other methods.