The Democratic Party of Japan (DPJ) came to power in 2009 with a commanding majority, ending fifty years of almost uninterrupted Liberal Democratic Party (LDP) rule. What explains the DPJ's rapid rise to power? Why has policy change under the DPJ been limited, despite high expectations and promises of bold reform? Why has the party been paralyzed by internecine conflict? This volume examines the DPJ's ascendance and its policies once in power. Chapters in the volume cover: DPJ candidate recruitment, the influence of media coverage, nationalization of elections, electoral system constraints on policy change, the role of third parties, municipal mergers, the role of women, transportation policy, fiscal decentralization, information technology, response to the Fukushima nuclear disaster, security strategy, and foreign policy.Japan under the DPJ makes important contributions to the study of Japanese politics, while drawing upon and advancing scholarship on a wider range of issues of interest to political scientists.Contributors include Kenneth McElwain (University of Michigan, USA), Ethan Scheiner (University of California-Davis, USA), Steven Reed (Chuo University, Japan ), Kay Shimizu (Columbia University, USA), Daniel Smith (Stanford University, USA), Robert Pekkanen (University of Washington, USA), Ellis Krauss (University of California-San Diego, USA), Yukio Maeda (University of Tokyo, Japan), Linda Hasunuma (Franklin and Marshall College, USA), Alisa Gaunder (Southwestern University, USA), Christopher Hughes (University of Warwick, UK), and Daniel Sneider (Stanford University, USA).