Cicero's Puzzle: Upper House Power in Comparative Perspective

his paper analyzes the legislative influence of upper houses in bicameral legislatures. We note the existence of two separate analytical traditions, one focusing on upper house expertise, the other on upper house power. We hypothesize that because legislative analyses of unitary systems focus primarily on the "efficient" aspects of upper house input, they tend to emphasize senatorial expertise. On the other hand, because legislative analyses of federal systems acknowledge the "political" dimensions of upper house power, they focus on senatorial power. We reunite the two analytical traditions and provide a unique model of upper house political power in both federal and unitary systems. For those states using a navette, or shuttle, system, we model senatorial power as a function of the institutional features of the system: stopping rules, where a bill is introduced, and the number of shuttles between houses are systematically related to upper house power. Potestas in populo, auctoritas in Senatu.