The decennial redistricting process has all the markings of power politics—at stake is the balance of power in Congress and state legislatures for the next decade. Behind the scenes is an array of actors who lend their political, legal, demographic, statistical, and cartographic expertise to legislators and decision makers who must navigate the complexities of election and redistricting laws. In their excellent new book Gerrymandering the States, Alex Keena, Michael Latner, Anthony McGann, and Charles Anthony Smith provide a much-needed investigation of redistricting of state legislatures following the 2010 Census, which deeply favored Republican candidates, or what has been referred to as the “Great Gerrymander of 2012” (p. 3). Their objective is to provide an account of what happened, why, the consequences, and whether gerrymandering can be prevented. They find that dozens of state legislative plans were drawn with extreme partisan bias and that this bias particularly benefited Republican state legislative candidates.

The authors draw their conclusions from a data set of outcomes on all upper and lower chambers of state legislatures and a series of tests to examine partisan bias. They consider not only the outcomes of the maps, but also institutional, political, and demographic considerations. Building upon prior work to delineate d