Sed quid custodes ipso custodiet? Who will guard the guardians? The question is not posed until nearly the end of this impressive new book, but it is clear from the outset that Paul Yowell is animated by a deep concern about the exercise of judicial power. He taps into the wellspring of anxiety about unelected judges making rights determinations, reviewing past critiques and developing new ones. His findings lead him to see little hope of restraining judges in their wide-ranging approach to the balancing tests inherent in rights-based judicial review. And thus, he asks, why have judicial guardians at all? His skepticism about rights-based judicial review leads him to the ultimate conclusion that constitutional designers should take more seriously the option of legislative supremacy in crafting new governance regimes.

Constitutional Rights and Constitutional Design raises important questions about the aspirations and efficacy of judicial review, and it serves as an excellent addition to the literature on judicial decision-making. Of course, any book with this breadth of coverage—moral reasoning, empirical analysis, history and law in multiple jurisdictions—and ambitious goal of intervening in many ongoing theoretical debates is bound to leave readers wanting more. And I hope here to highlight a few areas for further investigation in future work.

The core of the book presents a direct challenge to judicial power in the form of rights-based judicial review. Many scholars have engaged with the question of who is best placed to decide questions of rights—and Yowell adopts their methodology, conducting a comparative institutional analysis of “courts and judges” versus “legislatures and legislators.” He sidesteps Waldon on which institution best reflects democratic ideals (though one gets the sense they would be in agreement), but he takes on Dworkin in assessing who is best placed to conduct moral reasoning. And he adds a third new question altogether: He asks which institution is best placed to engage in the empirical reasoning needed to make the balancing and proportionality determinations that are demanded by rights-based judicial review.

Accepting that rights-based judicial review requires data to evaluate a state’s interest in legislation, Yowell’s broad claim must be right: a legislature will certainly have more access to general information than that provided to a court through amicus briefs, personal knowledge, or clerk- or librarian-conducted research. But access is only one part of the equation; how do judges and legislators evaluate or use that information? In critiquing the ability of judges and courts to engage with empirical data, Yowell in many ways reflects the empirical zeitgeist, where tales of p-hacking and replicability crises in multiple disciplines have called the ultimate endeavor itself into question. His negative assessment of the judiciary in this context is certainly fair, and he gives numerous examples of judicial confusion surrounding core concepts, including statistical significance. But his claim that legislators are better placed to review empirical work is less persuasive, in part because he compares actual judges (and their mistakes) with an idealized version of the U.S. Congress. He elides the information-gathering ability of Congress (through special entities, such as the Government Accountability Office, the Congressional Budget Office, and the Congressional Research Service) with legislators’ capacity to review the data. In fact, the recommendations of those bodies are sometimes affirmatively ignored; draft laws are often written by lobbyists and staffers; and, in some instances, legislators do not read—or have time to read—the bills on which they are voting, let alone the underlying empirical justifications.

One could focus on remediating the weaknesses of courts in these areas (a point Yowell notes, p. 154), but Yowell opposes the use of empirical data at the level of principle. The fact that courts have poor mechanisms to acquire this knowledge reinforces what appears to be Yowell’s real underlying concern: Constitutional interpretation should not rest on prudential or pragmatic analysis by drawing on the real-world consequences of legal decision-making. It is past legal decisions and the constraint placed by specific legal sources that “ultimately grounds [courts’] legitimate power” (p. 211). If judges were better at moral reasoning, then perhaps there would be a redeeming justification for judicial review, but because, in Yowell’s analysis, courts are not well suited to open deliberation on moral issues, there is little to justify rights-based review. The question is not who will guard the guardians, but why have judicial guardians at all?

Yowell acknowledges that the need to protect minority rights has been an affirmative claim for judicial review, but he discounts this argument. In the context of protecting racial minorities, he argues that the U.S. Supreme Court was not particularly successful, highlighting a litany of terrible cases in American history, such as Dred Scott, the Civil Rights Cases, and Plessy v. Ferguson, and drawing on the work of U.S. scholars who have argued that Brown v. Board of Education did little on its own to achieve desegregation. He notes, in contrast, that the U.S. Congress passed a number of important Civil Rights Acts in the ten years after the Civil War. Unfortunately, he does not assess its performance in later years. When the U.S. Supreme Court issued Plessy in 1896, the U.S. Congress had just finished passing a series of blatantly and cruelly racist laws in the Chinese Exclusion Acts. But it was the Supreme Court in Yick Wo v. Hopkins (1886) and Wong Kim Ark (1889) that upheld the constitutional rights of Chinese persons to equal protection and birthright citizenship. And while it is to the great credit of Britain that Parliament abolished the slave trade without needing judicial review, any causal inference is weak. Other variables—social context, differing legislative designs, the role of federalism—may provide the greater explanatory value.

Engaging with additional affirmative arguments might further complicate Yowell’s story. For example, John Hart Ely’s theory of judicial review builds on the concerns elaborated in Carolene Products Footnote Four (the genesis of the American rights-based balancing tests that Yowell critiques). Ely identifies a role for the Court in policing the political process, ensuring representation and core political rights (e.g., voting, speech). Others have proposed that the likely existence of legislative pathologies supports a weak form of judicial review; for example, courts may have a greater capacity in enforcing rights in light of blind spots or legislative inertia, protecting the legitimacy of the broader constitutional system.

Ultimately, Yowell makes a strong argument against U.S.-style judicial supremacy, driven in large part by concerns of irreversible error: Judges are prone to empirical and moral mistakes that will then be foisted upon the populace for perpetuity. But if there are any benefits to judicial review (as Ely and others would have us believe), then empirical questions abound: How much error is likely? Are decisions likely to be reversed by constitutional amendment? This kind of evaluation requires a more fine-grained institutional analysis that is contextualized in specific systems.

How much output error is there at the Supreme Court? If the error is to be assessed comparatively—i.e., does the Court err more than Congress?—then the answer is not clear. Scholars have claimed that the Supreme Court is never that far out of line with popular opinion, and the Court’s ability to control its docket allows it to avoid decisions that might force it to act contrary to popular will.  This fact might negate its value as upholding the counter-majoritarian aspiration (and Yowell argues societal pressure will interfere with seeking the truth of moral questions (p. 110)), but it also suggests that any mistakes are unlikely to be comparatively worse than those of the legislature. If the outcome-based comparative analysis is a toss-up, one might come down on the side of judicial review, if only to preserve the possibility for those rare but serious occasions when the political process breaks down, or legislative pathologies excessively burden rights.

As to the problem of perpetuity, Yowell is right to note that the U.S Constitution is one of the hardest to amend, but viewing the number of amendments over the duration of the constitutional regime might overstate the problem. In fact, rather than one amendment every 13 years (after the first 10), there have been pockets of amendment. There were four amendments between 1909 and 1919 and four between 1960 and 1971 (with a fifth—the Equal Rights Amendment—proposed in 1972). It may be that the United States has a variable amendment culture that changes over time, affecting the way the society thinks about constitutional change. Yowell also assumes a certain backdrop of legal formalism or perhaps legal fidelity, in which what the court says goes, and the legislature (and populace) defer. But it is not clear that this is the case, even in the United States. Noncompliance and court-curbing efforts, such as jurisdiction stripping, have been regular elements of the ongoing internal debate over judicial power.

The debate over judicial supremacy is a heated one, and Yowell has presented excellent new fodder for those critical of judicial power. It is a difficult transition, however, from an attack on one of the strongest systems of judicial review to generalizable lessons for constitutional designers. The United States could well be considered an outlier in matters judicial. Its version of judicial supremacy has developed over centuries, in part because of the nature of the federal system, in part because of contingent compliance from the populace, and in part because of a choice by the legislature (and sometimes the executive) to defer questions to the Court in order to deflect electoral ramifications. But most courts—especially new courts—are weak. In the famous words of Federalist 78, they have neither will nor power, but merely judgment. It should be of no great surprise that the Supreme Court struck down only one Congressional act in its first 60 years of operation—and that was a law that purported to expand the Court’s jurisdiction. (The Court itself could control compliance with its decision.) Its second foray into the judicial review of federal laws led to the Civil War.

The concern about judicial power has a certain nostaligia to it in an era of democratic backsliding and inroads on judicial independence. Elected officials are threatening courts in Turkey, Hungary, Poland, Brazil—and the legislative-led regimes that threaten to replace the courts are not paragons of rights protection.

Yowell’s gestures for constitutional design might work well for Waldronian societies that have functional democratic regimes and a shared commitment to human rights. To the extent that the United Kingdom is contemplating a written constitution, then Yowell’s suggestions may be apposite. But for states emerging from conflict or from authoritarian regimes, or with divided societies reflecting primordial cleavages, constitutional design requires a different set of assumptions.

Evaluating the options for constitutional design more broadly would require a more focused engagement with the origins and functions of judicial review in the constitutional design literature. Rights and structure become elements in a complex game of political and constitutional negotiation, and judicial review becomes a form of insurance for political elites as they try to control for future political and legal risk. In other contexts, an intentionally incomplete constitutionalism reflects an explicit choice to defer to courts in order to decrease the pressure on the bargaining parties to reach agreement on all issues. Federal systems provide for judicial review in order to police the federal bargain. In regimes emerging from authoritarianism, the judiciary might be needed to police the political process and work to facilitate the transition to democracy.

In some of these instances, rights review will be seen as an integral part of the constitutional bargain, perhaps because the legislature cannot be relied upon to protect minorities or to be non-pathological. In other examples, rights review might be argued to be optional, as it would be unconnected to the original purposes of judicial review in the specific system. And divided societies might seek out but ultimately be harmed by judicial review, as courts can reify and concretize divisions, especially regarding rights. A more thorough analysis of the different challenges faced by constitutionalizing systems would lead to a more refined set of institutional prescriptions for designers—and one that would be a welcome addition to the literature on constitutional design.

Professor Erin Delaney is Professor of Law at Northwestern University