The Brexit referendum, followed by Donald Trump’s 2016 victory and the rise of populists around the world, seems to indicate that politics is changing in fundamental ways in established democracies. Scholars have advanced two categories of explanations to account for these phenomena: economic and cultural. Among the economic causes, the most important are the effects of globalization and trade openness, rising inequality, and adverse income shocks generated by the Great Recession. Cultural issues, such as gender equality, the environment, self-expression, and tolerance toward foreigners and minority groups, are also considered to be important factors.

Focusing on cultural explanations, these two books by two renowned scholars examine and empirically test versions of modernization theory and document the rise of a new cultural cleavage. In Cultural Evolution, Ronald Inglehart explains how unprecedented prosperity led to cultural changes, the environmentalist movement, and the spread of democracy, as well as to the current reaction to modernization that has produced Trump, Brexit, and the rise of right-wing populists in various places. In Political Realignment, Russell Dalton analyzes the evolution of citizen and elite opinions on economic and cultural issues from the 1970s to the 2010s and how these changes have affected electoral politics and public policy in established democracies.

Inglehart and Dalton argue that modernization has dramatically changed the societies of established democracies, which have experienced unprecedented prosperity and security, rapid technological progress, and a massive increase in the proportion of educated people. More importantly, modernization has also transformed the cultural basis of contemporary societies by encouraging an openness to change, diversity, and new ideas. Nevertheless, modernization has also been a disruptive force, leading to deindustrialization and the marginalization of parts of society. Immigration from various parts of the world to the West has triggered a conservative counter movement, stressing the perceived loss of traditional moral values, social relationships, and sense of nation.

In Cultural Evolution, Ronald Inglehart presents a revised version of modernization theory. Whereas modernization theory holds that the transition from a “traditional” to a “modern” society is based on rational decision-making processes, Inglehart emphasizes the role of emotions and the experience of survival (in)security that various generations endure in their formative years. The more (or less) survival security that a cohort experiences in its formative years, the more (or less) likely it is to adopt “postmaterialist” (or “materialist”) values. Societies are transformed when younger birth cohorts replace the older ones in the adult population. Intergenerational value shift is also shaped by short-term economic booms or recessions. In addition, for Inglehart, cultural change is path dependent, because a society’s values are shaped by its entire history, rather than simply by its level of existential security. Furthermore, a society’s relative emphasis on self-expression versus survival explains how democratic it is.

The book uses the World Values Survey and the European Values Study from 1981 to 2014, covering more than 100 countries. The chapters document more or less smooth cultural change toward increased support for self-expression, greater individual autonomy, openness to diversity and new ideas, democratization, and—to a lesser extent—secularization over the past four decades. The final chapter also considers the rise of artificial intelligence in society, increasing global inequality, and their impacts on the future of democracy.

The book relies heavily on cross-country survey data but is missing a research design to identify the causes of cultural change. It does discuss the potential problem of adding the data from poor countries to that of rich countries: “Two effects work against each other here: (a) the presumed increase in measurement error that comes from including lower-income societies with less-developed survey research infrastructure—which tends to weaken the correlation between attitudes and predictor variables; and (b) the increased analytical leverage that comes from including the full range of societies—which tends to strengthen these correlations” (p. 6). However, this misses a bigger and more problematic point: the lack of control for unobserved heterogeneity can produce biased results. The presence of correlation due to unobserved heterogeneity is a pervasive problem in cross-country regression analysis. If characteristics that have a direct effect on both cultural change and economic development indicators are omitted, the explanatory variables will be correlated with errors, and regression coefficients will be biased.

Consequently, the empirical chapters of the book merely show some interesting correlations, not causations. For example, in chapter 5, it is hypothesized that the publics of economically developed societies are more likely to support individual-choice norms. However, one surprisingly discovers that the relationship between the economic growth rate and value change is negative. Inglehart suggests using the income level, rather than income growth, but a model in level will suffer from omitting the fixed effects. Likewise, in chapter 7, after discussing the limits of evidence on the causal link between democracy and development, Inglehart argues that “economic development is conducive to democracy insofar as it creates (1) a large and articulate middle class, and (2) transforms people’s values and motivations, so that they give higher priority on free choice and freedom of expression” (p. 117). However, as is well known, evidence based on cross-country data does not establish causation: some factor may determine both the economic development and democratization of countries. As discussed in the book, Acemoglu and his collaborators indeed, show that, once one includes country-specific fixed effects, there is no relationship between income and democracy.

The book could have used a research design to identify the causal determinants of cultural change, included fixed effects, or at least discussed the limits of using cross-country survey data. But because the book targets a large audience beyond scholars, it eschews those methodological checks. Despite these shortcomings, Cultural Evolution covers a myriad of topics, making it of interest to a wide range of readers. Its final chapters are of interest to social scientists researching Brexit, Donald Trump’s election, and the rise of populism.

To show that the party systems of today are fundamentally different from the party systems of the 1970s in established democracies, Russell Dalton examines how the demand and supply of democratic representation have adapted and reacted to social modernization. A central theme in Political Realignment is the interaction between social modernization and cultural change. The latter broadly reacts to and is shaped by the former, but once partisan patterns are set, party alignments can affect citizens’ cleavage positions in a partial feedback loop, leading to a cultural dimension that now rivals the historic economic cleavage as the basis for electoral choice.

Using data from the European Elections Studies, Dalton shows that public opinion on specific issues reflects deeper economic and cultural cleavages. Citizens’ economic positions have only modestly changed over time as the working class share of the public has decreased and the median voter has shifted toward the growing middle class. On the cultural dimension, the young, better-educated professionals and managers are strong advocates for liberal cultural values against farmers, retirees, manual workers, and religious citizens, who are on the opposite side of this division. Moreover, citizens are more polarized on the cultural dimension, making it the dominant cleavage in contemporary politics. According to Dalton, the root causes of this cleavage are not related to short-term reactions to deeper EU integration, concerns about the consequences of the 2008 financial crisis, globalization, or the growing numbers of immigrants in Europe. Instead, they are reflections of a wider conflict between the pros and cons of modernization.

Various chapters of the book document the rise of a cultural dimension among citizens, the elite, parties, and across European nations. After analyzing the demand side, the book focuses on the supply side of democratic representation and addresses the question of how political choices in Europe have evolved over time. Based on elite data, chapter 5 shows that citizen-defined and elite-defined perceptions of the policy space are broadly identical. The cultural cleavage shows a realignment of group positions, in which manual workers joined farmers and business owners in favoring conservative cultural positions.

The second part of the book studies political parties and shows that party competition increasingly occurs within this two-dimensional policy space defined by economic and cultural divisions. Whereas in 1979 the economic dimension was the dominant basis of party competition, a party realignment on the cultural dimension became more distinct by 1994, when Greens, New Left parties, and several social democratic parties adopted culturally liberal positions. The diversity of party positions across the two cleavages has increased the options available to voters, improving political representation.

The important topic of representation and voter–party congruence is analyzed in chapter 8 from both macro and micro perspectives. It suggests that, when analysis is conducted from the macro perspective, one finds a strong voter–party congruence, but substantially less congruence is found when considering the micro perspective. Finally, to broaden the scope of the evidence, the penultimate chapter of the book also considers the evolution of political cleavages and party choices in the United States; it shows that, just as in Europe, an economic and a cultural dimension characterize the policy space in the United States.

Although many scholars are concerned about volatility and instability in the current party system in advanced democracies and see signs of party-system failure or even signs of liberal democracies being in crisis, Dalton is optimistic. For him, the world has changed, and it is now more complex than it used to be. Consequently, the stable party system of the past is less applicable to more varied and dynamic modern party systems. In a more dynamic process of competition within the two-dimensional cleavage, parties respond to changes in citizen demand, leading to a high congruence between voters and their chosen party.

The final chapter of Dalton’s book, like that of Inglehart’s, discusses political realignment of party systems and its implications for the future of electoral politics in established democracies. It predicts more volatility in campaign programs, in voter choices, and in electoral outcomes.

Political Realignment does an excellent job in identifying and documenting a fundamental change from a simple, one-dimensional setting to a more complex two-dimensional policy space defined in economic and cultural terms. However, in contrast to many scholars who describe this change as caused by economic factors such as globalization, Dalton dismisses the role of recent economic factors, without providing any empirical evidence for doing so. An important question that remains unanswered is whether the electoral volatility and the rise of populism are transitory or more enduring phenomena. In other words, will politics in advanced democracies remain volatile, complex, and multidimensional, or will they converge to a new one-dimensional world defined by cultural issues?

These two ambitious books by renowned political scientists are of interest to anyone interested in understanding the dynamics of cultural evolution and electoral change, as well as the rise of a new cultural cleavage around the world.