ABSTRACT
This paper applies the concept of Evolutionary Stable Strategies (ESS), developed by Maynard Smith and Price (1973) and popularized by Dawkins (1976), to explain the persistence of inefficient, suboptimal, or seemingly irrational legal arrangements.
Unlike previous evolutionary theories of law that failed by treating legal rules as organisms subject to natural selection, we demonstrate that certain legal configurations persist because they constitute ESS-strategies that, once adopted by a sufficient proportion of actors, cannot be displaced by alternative strategies.
Through game-theoretic modeling and empirical evidence from Argentine legal history, we identify three primary legal ESS: precedent systems that self-reinforce through path dependency, informal influence networks that create participation incentives preventing reform, and theatrical compliance that satisfies formal requirements while preserving substantive deviations.
Our analysis reveals that legal ESS exhibit the key mathematical properties identified by Maynard Smith, functioning as Nash equilibria that remain stable against invasion by mutant strategies. This framework explains why certain suboptimal laws persist despite their social costs and why legal reforms often fail unless they account for the underlying strategic equilibrium.
The paper concludes by identifying conditions under which legal ESS can be disrupted and replaced, offering practical insights for legal reform efforts that acknowledge strategic realities rather than assuming rational legal evolution.
Lerer, Ignacio Adrian, Why Bad Law Persists: Evolutionary Stable Strategies in Legal Systems (September 13, 2025).
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