The Great Leveler

Walter Scheidel argues that across recorded history, only massive violent disasters have reduced inequalities of income and wealth on a large scale. He opens by noting that in 2015, 62 billionaires owned as much as the poorest half of humanity, and that inequality has been growing across much of the world. He calls the four principal agents of leveling the "Four Horsemen of Leveling": mass mobilization warfare, transformative revolution, state failure, and lethal pandemics. He contends that no peaceful mechanism has ever achieved comparable results. Scheidel relies primarily on two metrics: the Gini coefficient, which measures the distribution of income or wealth on a scale from 0 (perfect equality) to approximately 1 (maximum inequality), and top income or wealth shares.

Scheidel begins by tracing inequality to its deep origins. Among the African great apes, dominance and unequal access to resources are the norm. Over the last two million years, however, developments among human ancestors, including projectile weapons, coalition-building, and language, eroded physical dominance and produced an egalitarian equilibrium among hunter-gatherer groups. Contemporary foraging societies maintain low inequality through deliberate leveling mechanisms including gossip, ridicule, and sharing norms.

This egalitarian order was shattered by what Scheidel calls the "Great Disequalization": the transition to food production beginning around 11,500 years ago. Farming and herding created defensible, heritable productive assets. A study of 21 small-scale societies found that composite wealth Gini coefficients averaged only 0.25 to 0.27 for hunter-gatherers but rose to 0.48 for agriculturalists. State formation then amplified these disparities, as rulers and elites enriched themselves through taxation, corruption, war booty, slavery, and forced labor. Scheidel examines Han China and the Roman Empire to show how political power drove wealth concentration. In Rome, the largest private fortunes grew fortyfold in two centuries as the empire expanded. Across 28 preindustrial societies, the average "extraction rate," the proportion of theoretically possible inequality actually realized, reached 77 percent.

Surveying long-run trends, Scheidel identifies two secular peaks in European inequality: the mature Roman Empire and the eve of World War I, separated by compressions caused by imperial collapse and plague. After the Black Death temporarily doubled wages in the mid-fourteenth century, inequality rose again for roughly four centuries. Tax records document this ascent: In the Dutch city of Leiden, the top 1 percent wealth share grew from 21 percent in 1498 to 59 percent in 1722. By 1914, top income and wealth shares had been increasing for centuries across most documented countries.

The central chapters analyze each horseman in turn. Scheidel presents Japan during and after World War II as a paradigmatic case of leveling through mass mobilization warfare. The top 1 percent income share fell from 19.9 percent in 1938 to 6.4 percent in 1945, driven by government regulation that created a planned economy, inflation that eroded capital income, and physical destruction from bombing. American occupation reinforced wartime leveling through dissolution of the zaibatsu (family-owned business conglomerates), confiscatory property taxes, land reform, and labor reforms. This pattern was widespread: Across more than 20 countries, World War II produced an average drop of about 31 percent in top 1 percent income shares. The wars also spawned steeply progressive taxation, and Scheidel argues that postwar unionization, welfare state expansion, and franchise extensions were direct outgrowths of the conflicts. The Cold War further disciplined inequality through competition with the Soviet bloc. By contrast, traditional premodern wars of plunder and conquest typically enriched victorious elites rather than reducing inequality.

The second horseman, transformative revolution, produced radical equalization through extraordinary violence. Scheidel traces the Russian Revolution from Bolshevik leader Vladimir Lenin's 1917 decree abolishing private landownership through the collectivization drive of his successor, Josef Stalin, which by 1937 encompassed 93 percent of Soviet agriculture at a cost of millions of lives. The Soviet market income Gini fell from about 0.36 around 1905 to the mid-0.2s by the late 1960s, then nearly doubled to 0.51 by 1995 after the Soviet Union's collapse. In China, communist leader Mao Zedong's land reform between 1947 and 1952 killed between 1.5 and 2 million people and transferred close to half of all farmland. Cambodia under the Khmer Rouge, the country's communist regime, represented the most extreme case, with approximately a quarter of the population killed. By contrast, the French Revolution produced only moderate leveling, and premodern peasant revolts almost never achieved significant redistribution.

State failure and systems collapse constitute the third horseman. Because elites derived wealth from both economic activity and political connections, the collapse of state structures destroyed both income streams simultaneously. The terminal phase of the Tang dynasty illustrates this: Serial sackings and purges systematically destroyed a metropolitan aristocracy until the entire central ruling class vanished from the historical record. The disintegration of the western Roman Empire similarly wiped out a super-rich senatorial class. Archaeological evidence from Britain shows that house size inequality increased dramatically under Roman rule and then collapsed after Roman withdrawal.

The fourth horseman, lethal pandemics, leveled inequality by altering the ratio of land to labor. The Black Death, which killed more than a quarter of Europe's population by 1400, roughly doubled urban real wages by the mid-fifteenth century. Italian tax records show Gini coefficients dropping by more than 10 points. However, this leveling was temporary and depended on institutional context: In western Europe, serfdom declined as workers leveraged their scarcity, while in eastern Europe, nobles imposed serfdom. The Justinianic Plague (541 to approximately 750 CE) produced similar effects, with Egyptian evidence showing that wages roughly tripled in its aftermath.

Scheidel systematically evaluates peaceful alternatives and finds them inadequate. In a survey of 27 land reforms during the second half of the twentieth century, inequality either remained unchanged or grew in 78 percent of cases. The most comprehensive study of democracy and inequality, covering 184 countries from 1960 to 2010, finds no consistent effect. Economic crises show no systematic tendency to reduce inequality. Latin America offers the most promising recent case, with declining income Gini coefficients in the early 21st century, but this trend has stalled or reversed since 2010 and was driven partly by recovery from prior crises and favorable but transient commodity markets.

Documenting the resurgence of inequality since approximately 1980, Scheidel shows that in a sample of 26 countries, top income shares grew by half between 1980 and 2010. In the United States, 60 percent of market income growth between 1979 and 2007 was captured by the top 1 percent. Multiple forces drive this trend, including globalization, declining union membership, falling top tax rates, and technological change. Scheidel proposes counterfactual scenarios and argues that without the violent shocks of the twentieth century, any temporary dip in inequality would likely have been reversed by disequalizing pressures from technological change and globalization.

Looking to the future, Scheidel concludes that all four horsemen are currently dormant. Military technology favors professional forces over mass mobilization, nuclear deterrence discourages large-scale war, transformative revolution has gone out of fashion, and state failure on a historically significant scale has become rare. Future pandemics would likely be far less lethal than premodern plagues. Scheidel reviews policy proposals for reducing inequality but observes that most lack political feasibility, and warns that emerging technologies such as artificial intelligence could create new forms of inequality. He closes by arguing that peaceful policy reform may prove insufficient to reverse the trajectory of rising inequality, even as the violent alternatives remain unconscionable.