James Gimpel and Jason Schuknecht are on a mission to revive the study of U.S. political geography. In their book, the duo make a compelling case for what party strategists, candidates, and pundits already know: Place matters generally and, sometimes, significantly. The authors, however, take readers far beyond a simplistic “Maryland-is-different-from-Arkansas” viewpoint or a red- versus blue-state dichotomy to a sophisticated and nuanced investigation of sectionalism.

Gimpel and Schuknecht analyze geographical foundations of state electoral systems, finding that regional cleavages are growing in some states and declining in others, with substate sectionalism generally on the rise. To identify political regions (defined as the similarity of political party support among a region's citizens), they rely on the compositional school of political geography, arguing that regions are the product of various racial, ethnic, class, and ideological groupings. While sensitive to contextual explanations (place has an independent effect beyond demographics), the pair regard contextual effects as secondary to compositional ones in explaining substate sectionalism. They show how sectionalism affects partisan mobilization strategies—noting generally that Republican identifiers are geographically dispersed in more states than are their Democratic counterparts. Consequently, Republicans must spend more to mobilize their faithful. As students of electoral change, the authors use conventional party realignment theory—conversion, mobilization, and generational replacement—to explain substate sectionalism. To this trio, they add population mobility, an explanation well matched to the book's political geography theme and one that they have explored (James G. Gimpel and Jason E. Schuknecht, “Interstate Migration and Electoral Politics,” Journal of Politics 63 [February 2001]: 207–31).

Patchwork Nation is a 12-state study (California, Colorado, Connecticut, Florida, Georgia, Illinois, Maryland, Michigan, Minnesota, New York, Oregon, and Texas). These states differ in significant ways: size, electoral college importance, geographical locale, political culture, party competition, and socioeconomic makeup. Because the authors study political change from 1928 to 2000, they must employ aggregate election and census data as polling data from the early period do not exist. To formulate generalizations at the individual level and avoid the ecological fallacy problem, they use the ecological inference solution (Gary King, A Solution to the Ecological Inference Problem, 1997). For the later years, they also utilize polling data to check the reliability of the aggregate data estimates.

From these data come a dizzying array of findings. For example, California became more sectionalized, transforming itself from a north–south division to four regions (north, south, coastal, and central). The forces driving these changes are extraordinary population mobility and racial diversity. Conversion and generational replacement also fueled change in the Golden State's electorate; nearly all of these factors benefit Democrats. In stark contrast stands Texas, where population mobility coupled with mobilization, conversion, and generational replacement diminished sectionalism. These factors also brought two-party competition and Republican dominance. Each of the 12 states combines population mobility, generational replacement, conversion, and mobilization in unique ways, resulting in a “patchwork” nation.

Despite highly specific state findings, cross-state generalizations emerge. In-migration almost always assists the Republican effort, as citizens who are mobile are more likely to have means, while those with modest resources are less likely to move. In-migration has generally made sectionalism a less important force in state politics as many in-migrants have settled in suburban locations where their Republican predilections run counter to central-city dwellers in the same region. Gimpel and Schuknecht find that mobilization matters most in jurisdictions with significant African American populations; moreover, mobilization of black voters is related to the importance of conversion of white voters.

While the findings demonstrate the importance of electoral geography, the authors gloss over the significance of religion and religiosity in contributing to substate sectionalism. They mention on multiple occasions that religion has been and can still be a source of sectionalism. Although they understand that the conversion of Southern (Texas, Georgia) and working-class (Michigan) whites to the GOP pivots on conservative religious mores and race, they fail to investigate religion systematically. Additionally, a case can be advanced that mobilization of white evangelicals made sectionalism less crucial to state politics. Unfortunately, no attempt is made to assess the impact of religion or, more important, religiosity (what impact does aggregate church membership, for example, have in making some regions distinctive?). Aggregate data on church membership are available for much of the period, albeit not from the U.S. Census (see, for example, Religious Congregations and Membership in the United States: 2000, 2002). Moreover, prodigious research has resulted in sophisticated categorization of religion other than the Protestant-Catholic-Jewish trichotomy (John C. Green et al., Religion and Culture Wars: Dispatches from the Front, 1996). If religion were considered, it might shed light on the growing Republicanism of rural areas and why manufacturing workers in some states behave differently than they do in others.

The book's lofty ambitions are both a strength and a weakness. The various themes of sectionalism and political change are not well connected in individual state chapters, making the text difficult for the reader to follow. Because it appears that the state chapters were written to stand alone, a maddening array of redundancy results. Many estimates derived via the ecological inference model are not reliable, making the authors press the data for explanations (for example, estimates for immigrants are unreliable in several states). As a result, their conclusions are filled with caveats.

Nevertheless, the book is important because it does not shy away from empirically interesting but difficult questions. Patchwork Nation speaks to a variety of audiences: political scientists, political consultants and commentators, and party officials. It is an accessible volume that could be used in advanced undergraduate courses in state politics and political behavior, as well as in graduate seminars on U.S. politics.