The importance of political geography is likely to see renewed attention amid the redistricting cycle following the 2020 census and the controversies that new constituency maps are likely to bring. Many argue that gerrymandering in the United States is a key cause of electoral polarization and the observation that Democrats often are legislatively underrepresented relative to their aggregate vote shares. Jonathan Rodden convincingly shows that although gerrymandering may be a factor at the margins, the primary cause of these patterns is an urban-rural political divide that causes a political geography problem for Democrats.

Rodden makes this case by showing historically how party platforms and constituencies evolved and illustrating the implications for political geography. This historical tracing of the parties speaks to how the battle between Republicans and Democrats came to be a culture war. This starts with the Democrats’ historical position as the party of laborers. Since factories were concentrated in cities, Democratic politicians who wanted to maintain their seats had to adopt positions that were appealing to growing portions of urban populations, taking progressive positions on social issues in addition to representing the interests of laborers. As the economy has shifted, the Democrats’ urban coalition has remained, with Republicans finding appeal in rural and exurban areas. The United States is not alone in this phenomenon. Rodden shows that nations such as the United Kingdom, Canada, and Australia—all of which also conduct single-member plurality elections— have also seen left-of-center parties become urban parties with similar geographic patterns in constituencies.

To facilitate this story and to describe the status of today’s parties, Rodden also includes intuitive analysis of political geography using maps and scatterplots of vote shares by precincts. These figures illustrate key findings, such as the fact that party vote shares by precinct are more varied outside major cities. The maps show how legal principles such as compact districts interact with these patterns: urban areas that are overwhelmingly Democratic often fill the entirety of compact legislative districts and produce wasted votes for Democrats that are well beyond what is needed to win a given seat. Meanwhile, suburban and rural areas show more variance, so Republicans typically win by closer margins without many wasted votes.

Under the current political alignment, for Democrats to have seat shares that consistently correspond with vote shares, they would need to push for one of two electoral reforms: one would be proportional representation of some type, which would allow large vote totals from cities to translate better into seats while more divided rural areas might produce fewer Republican seats. The other would be to eliminate rules for compactness in districts, allowing highly Democratic urban areas to be broken up into districts that contain a discernible minority of Republican-oriented voters.

Overall, this book offers a clear and intuitive explanation of the political geography issues facing left-of-center parties in first-past-the-post electoral systems. In the American context in particular, Rodden also offers one of the most logical, plausible, and empirically supported explanations for rising polarization and culture wars between the parties. Why Cities Lose offers a clear picture of political geography that both scholars and practitioners should be able to appreciate. After the 2020 census, the American states will enter another round of legislative redistricting. To anyone who wants to understand the underlying dynamics for the coming process and the stakes for the two parties, Rodden’s book is an important read.