Ran Hirschl and the Possibility of a More Rigorous Comparative Constitutional Law

Arvind Kurian Abraham

SJD Candidate, Harvard Law School.

The field of comparative constitutional law has lost one of its most rigorous and provocative voices. Ran Hirschl, whose scholarship relentlessly pressed the discipline to examine its own methodological foundations, left behind a body of work that fundamentally altered how scholars think about what comparative constitutional law is, what it does, and what it ought to aspire to. At a time when much comparative scholarship was driven by intuition, anecdote, and doctrinal fascination, Hirschl insisted that the field ask harder questions about method. He challenged comparative constitutional lawyers to take case selection seriously, to be explicit about causal claims, and to borrow the tools of the social sciences rather than relying on impressionistic comparisons.

One of his most enduring contributions was his typological mapping of the forms that comparative constitutional scholarship takes in practice. Rather than treating the field as a unified enterprise, he disaggregated it into four distinct types. The first type is the standalone analysis of a jurisdiction different from that of the author, work that is often mistakenly labelled comparative constitutional law, even though it involves no genuine comparison at all. In this genre, methodological choices in terms of case selection are simply overlooked. The second type is what most judges practice: self-reflection and the betterment of one’s own constitutional order through analogy, distinction, and contrast with other jurisdictions. Trends such as “inter-court borrowing” fall under this category, with references typically drawn from “stable constitutional democracies” such as the United States, Germany, and Canada. Hirschl’s critique here was sharp and apt. This approach rarely pays meaningful attention to the context in which foreign decisions were rendered, and references to foreign jurisprudence are frequently superficial in nature. The decisions were mined for convenient analogies without serious inquiry into the political, historical, and institutional soil from which they emerged.

The third type was more academically serious: a universalist approach to “concept formation through multiple description,” examining how constitutional concepts like separation of powers or equality manifested across multiple legal systems. Hirschl pointed to the comparative constitutional law casebook of Vicki Jackson and Mark Tushnet as a paradigm example. He acknowledged its value in generating thick conceptual understanding, but argued that it still fell short of genuine scientific inquiry because it did not seek to make inferences about cause and effect.

It was the fourth type that Hirschl regarded as the field’s most defensible aspiration: “theory building through causal inference.” For Hirschl, “causal inference” carries its social-scientific meaning: the formulation of testable hypotheses about why constitutional phenomena occur, and their confirmation or disconfirmation through controlled comparison and systematic case selection, aimed at explanation rather than mere description. This was where his contribution was at its richest.

Hirschl advocated for a detailed architecture of case selection drawn from social science methodology. The “most similar cases” approach isolates the explanatory power of a particular variable by selecting jurisdictions that resemble each other in most respects, as with comparing the United States and the United Kingdom to study the impact of judicial review. An important illustration of this method according to Hirschl was Tom Ginsburg’s Judicial Review in New Democracies, which studied Taiwan, South Korea, and Mongolia. The three jurisdictions shared a similar cultural context and had each transitioned to democracy in the late 1980s and 1990s, holding those variables constant. Yet there was considerable variance in the development of judicial independence among them, which Ginsburg attributed to differences in political conditions rather than macro-cultural or societal factors. It was the methodological discipline of the case selection that made this causal claim possible.

The “most different cases” approach selects jurisdictions that differ on most variables but share the key variable under study, so that if a similar outcome is observed across both, it can be attributed to that shared factor rather than to any of the other differing variables. For instance, Chile and Türkiye are very different in terms of geography, culture, and legal tradition, but they share a common experience of military rule and transition to democracy. According to Hirschl, a comparison of these two jurisdictions would allow a researcher to attribute similar patterns of judicial deference toward the executive to that shared authoritarian history, having effectively ruled out other possible explanations.  

“Prototypical cases” allow for representative analysis across legal families. Mitchel Lasser’s Judicial Deliberations exemplifies this approach, taking the United States Supreme Court as prototypical of common law systems, the Cour de cassation for civil law systems, and the European Court of Justice for supranational law systems.

The “most difficult cases” approach stress-tests a theory against the evidence most likely to defeat it. If the theory holds even under such adverse conditions, its validity is substantially enhanced. Gerald Rosenberg’s Hollow Hope exemplifies this method. Rosenberg tested his thesis that the United States Supreme Court has been unable to effect significant social change by subjecting it to the case most commonly cited as the Court’s milestone decision, and hence a counterexample of Rosenberg’s own contention: Brown v. Board of Education. Rosenberg went on to argue that desegregation was ultimately achieved not by the ruling itself but by the extra-legal activism of African Americans.

The “outlier cases” approach looks at cases that existing theory cannot explain, treating such anomalies as the raw material for new theoretical construction. Hirschl deployed this method with particular power in his own work, Towards Juristocracy. His theory of juristocracy argued that the spread of constitutional rights regimes was frequently driven not by a liberal democratic impulse, but by political elites seeking to entrench their hegemony against electoral uncertainty. The theory was itself a product of the outlier case method: Hirschl identified jurisdictions that had experienced rights revolutions without major shifts in their political regimes, cases that standard theories of post-war reconstruction or decolonization could not account for. His analysis of Israel’s adoption of constitutional review in 1995 and the secular elite’s strategic use of the Supreme Court’s jurisprudence to preserve dominance in the face of electoral pressure from the religious masses was a demonstration of what rigorous causal reasoning could illuminate.

Those who engaged with Hirschl most seriously, including Professors Vicki Jackson and Theunis Roux, acknowledged the force of his diagnosis, even while questioning whether the social scientific prescription fits the nature of law. Jackson rightly observed that legal reasoning is deontological: the grounding of justice is essential to law in a way that sets it apart from the forms of causal inference prized by the social sciences. Roux noted that many valuable forms of comparative constitutional scholarship, including doctrinal constructivism aimed at building constitutional doctrine from comparative experience, do not share the objectives of social science and should not be required to. 

In my opinion, constitutional law is a product of political environment, history, and culture in ways that resist clean variable isolation. A large section of legal scholarship aims to explain causal connections between a set of variables and legal or judicial outcomes. However, to insist that such claims must withstand falsifiability testing in line with social science methodology excludes other valid approaches, such as a historical analysis that identifies the dispositive factors of a particular judicial decision or legal phenomenon. Historical analysis examines how social and political factors within specific time periods shape law. Take, for instance, Linda Colley’s work explaining the link between written constitutions and the changing methods of warfare after 1700. Even without engaging in strict isolation of variables, such scholarship can offer useful insights. However, it must be noted that Hirschl, to his credit, agreed that law cannot be a science, though he rightly maintained that this was no excuse for ignoring rigorous method.

What Hirschl gave comparative constitutional law, above all, was the demand for honesty — about what one is comparing, why those cases were chosen, and what the analysis can and cannot establish. That is an inheritance worth keeping.

Arvind Kurian Abraham is an SJD candidate at Harvard Law School.

Suggested citation: Arvind Kurian Abraham, ‘Ran Hirschl and the Possibility of a More Rigorous Comparative Constitutional Law’ IACL-AIDC Blog (16 June 2026) https://blog-iacl-aidc.org/2026-posts/2026/6/16/ran-hirschl-and-the-possibility-of-a-more-rigorous-comparative-constitutional-law