Are State Legislative Leaders Moderates?

Abstract

Spatial models of legislative organization predict that elected leaders will be moderates with respect to their constituency, the party caucus. However, empirical studies of leader positioning in Congress find mixed evidence that this is the case. This paper expands the analysis to state legislatures, using an original dataset of 2056 top chamber and party leaders in 50 states from 1999 to 2023. Simulations reveal that state legislative leaders are consistently moderate relative to their caucus. Furthermore, while Democratic leaders consistently occupy the moderate left side of their caucus, Republican leaders do not show the same pattern, with some even positioned to the left of their caucus median. Beyond this overall pattern, there is substantial variation in leader-caucus ideological divergence. The analysis shows that increasingly distinct and homogeneous majority parties—fulfilling the conditions of conditional party government theory—are consistently associated with leader moderation. However, this effect is stronger for Republicans than for Democrats, which is inconsistent with the theory's predictions of party symmetry. Finally, using a new dataset on majority party roll rates, the spatial divergence of majority party leaders from their caucuses is found to lead to significant failures of agenda control, with a substantial increase in majority party rolls for moderate Republicans but not for Democrats. This finding contradicts the predictions of party cartel theory, which suggests no differences in agenda control based on leader ideology or party. The evidence consistently shows substantial asymmetry between Republican and Democratic leaders.