The forthcoming article “A theory of political divergence and gradual institutional change” by Clair Yang is summarized by the author below.
Many societies in history were ruled by kings, emperors, or aristocrats. Yet over time, they evolved in strikingly different ways. Why did medieval Europe gradually move toward representative institutions and parliaments, while imperial China transitioned from a once aristocratic society to one dominated by a centralized bureaucratic state? Why did some societies manage to break away from historical constraints while others did not?
This paper combines both formal theory and illustrative historical case studies to explain these divergent political trajectories.
The core argument is simple: political institutions and social structures evolve together over time. In the short run, rulers must survive by building coalitions. Sometimes they ally with powerful nobles; other times they cooperate with weaker groups in society to counterbalance entrenched elites, creating what I call “weak-coalition autocracies.” But the coalitions they build in the short run can slowly reshape the underlying balance of power itself, leading to enormous long-term consequences.
The interaction between short-run and long-run forces generates distinct pathways. Some institutions become self-enforcing. They stabilize society and reproduce themselves over generations. Others are self-undermining: they gradually strengthen the very groups that may later challenge the regime.
A key insight of the paper is that many historical institutions functioned like “inheritance taxes” on political power. Under primogeniture, the son of a duke typically becomes the next duke. But the son of a Mamluk general is generally disqualified from joining the ranks, while the son of a Chinese minister may spend years, even decades, preparing for a highly competitive exam. Systems such as the imperial examination system of China or the Mamluk military institutions in medieval Muslim states systematically reshuffle the elites and prevent powerful families from monopolizing authority. These institutions allowed rulers to recruit new allies from outside the small circle of elites and limit the long-run accumulation of elite power.
More broadly, the paper suggests that political development is neither entirely predetermined nor purely accidental. The paper offers a way to think about “critical junctures,” a term historians and political scientists often use to describe turning points in history. Shocks matter, but their effects depend on underlying social structures and institutions. In some places, the impact of a shock gets gradually absorbed by the system. In others, it triggers a chain reaction that pushes society “across the Rubicon.”
Small differences in institutions and social structures can accumulate over centuries, producing very different worlds from surprisingly similar beginnings.
About the author: Clair Yang is a Long Endowed assistant professor of political economy at the Jackson School of International Studies at the University of Washington in Seattle. Their research “A theory of political divergence and gradual institutional change” is now available in Early View and will appear in a forthcoming issue of the American Journal of Political Science.