This study of the influence minority parties wield is both a major work of political science scholarship and a timely examination of an issue with real consequences for the functioning of democratic legislatures and the creation of legislation. Challenging conventional assumptions that the majority party dominates the legislature, Jennifer Hayes Clark investigates precisely the ways in which--and under what conditions--members of the minority party successfully pursue their interests. For this study, Clark collects fine-grained data from both the U.S. Congress and state legislatures to get a close look at three key points in the legislative process: committee assignments, bill cosponsorship, and roll-call votes. She finds that minority party members are not systematically excluded throughout the policymaking process. Indeed, their capacity to shape legislative decision-making is enhanced when party polarization is low, when institutional prerogatives are broadly dispersed rather than centralized, and when staff resources are limited. Under these conditions, bipartisanship bill cosponsorship and voting coalitions are also more prevalent.--