From the ashes of the Nazi regime in Germany rose a new constitutional order designed to prevent the horrors of fascism from returning to German politics. Having experienced the consequences of a political system that lacked effective constraints on state power, the legal scholars and political leaders tasked with writing Germany’s new constitution – what would become known as the “Basic Law” (Grundgesetz) – set about constructing a new constellation of political institutions that would act to limit any future attempts at pushing state power beyond constitutional boundaries (Brecht Reference Brecht1949; Collings Reference Collings2015; Friedrich Reference Friedrich1949). As an expression of this foundational goal, the first article of the Basic Law set out three core tenets of the new German democracy: human dignity, human rights, and the obligation of the political system to respect the rights enshrined in the Basic Law.Footnote ¹ And throughout, one theme in particular permeated as a priority: the rule of law (Grote Reference Grote, Silkenat, Hickey and Barenboim2014).

Yet ensuring that state respect for these rights and the rule of law posed the true challenge. After all, the Weimar Constitution had similarly provided for individual rights (Maier Reference Maier2019), yet it had failed to prevent the Nazis’ ascent to power. Learning from the lessons of the Weimar Constitution’s shortcomings while building on past German experience with judicial review (Kommers and Miller Reference Kommers and Miller2012), the designers of Germany’s new constitution turned a newly established constitutional court to serve as the “Hüter des Grundgesetzes”: the guardian of the Basic Law. This new Federal Constitutional Court (Bundesverfassungsgericht), empowered to nullify government actions, was thus born to “ensure respect for and give effect to Germany’s free democratic basic order” and “to limit state power” (German Constitutional Court 2024).

The Court has since flourished in this role. Scholars and practitioners alike frequently refer to it as one of the most consequential institutions in German politics and influential constitutional courts in the world (Kommers Reference Kommers1994; Vanberg Reference Vanberg2005). Indeed, so immediately clear was the court’s capacity to constrain executive power that Germany’s first post-war Chancellor, Konrad Adenauer, went so far as to describe the court as “the dictator of Germany” (Vanberg Reference Vanberg2000).Footnote ² Similarly, when the Court celebrated its fiftieth anniversary on September 28, 2001, the keynote speaker, Gerhard Casper, declared that “If cities are to define German republics, then please allow me – at least for today and on this occasion – to choose the city of Karlsruhe, where the Federal Constitutional Court is located” (Casper Reference Casper2001). And if imitation is a reflection of success, the replication of the German court’s design and structure in new democracies from post-Soviet Europe to East Asia reflects the court’s consistent position as an effective bulwark against those who would challenge the constitutional bounds of state power.

Such continued success does not arise by virtue of the mere existence of judicial review. Rather, the capacity of a court such as the Bundesverfassungsgericht to effectively impose constraints requires, as Vanberg (Reference Vanberg2005, 121) quotes a German member of parliament describing it, the ability to give elected officials “a bloody nose” if necessary. This need to translate judicial review’s promise into reality raises important questions. How is it that a court can effectively harness the power of judicial review to compel executives to remain with in the constitutional limits of their authority? What allows judicial review to be transformed from a legal proceeding into a politically relevant exercise of judicial authority? Under what conditions is this efficacy likely to flourish – or to wilt? And how can courts fulfill such a role as “defenders of the constitution” in the face of powerful political forces like partisanship? Answering these questions is the central goal of this book.

The Rise of Constitutional Courts and Judicial Review

Judicial review was once considered an anomaly of the North American experience, but it has since expanded remarkably such that it is now considered a hallmark of modern liberal democracy.Footnote ³ Germany was not alone in its transformation to a constitutional system guarded by judicial review. As the world emerged from World War II, the importance of state constraint was a topic of great concern. Across Europe, parliamentary supremacy had been the dominant form of government; the war demonstrated its deficiencies in a terrifying way (Gardbaum Reference Gardbaum2014; Lutig and Weiler Reference Lutig and Weiler2018). As a result, states across Europe adjusted their systems of government in the years after the war. Whereas granting courts – or a single court – the constitutional authority to nullify the actions of duly elected officials had been anathema to many legal thinkers, such judicial power quickly became a staple of a renewed form of liberal democracy. Just as the Germans had integrated a constitutional court into their new post-war political system, so too did the Italians (Volcansek Reference Volcansek1994) and, a few decades later, the French (Stone Reference Stone1992) in the form of the Conseil Constitutionnel. Likewise, democratizing countries from South Korea (Ginsburg Reference Ginsburg2003), to Poland (Schwartz Reference Schwartz2000), to Spain (Garoupa, Gomez-Pomar, and Grembi Reference Garoupa, Gomez-Pomar and Grembi2013) made the adoption of judicial review a central component of their refounded democratic systems. These and many other countries empowered judiciaries as a failsafe against executive or legislative aggrandizement (Cappelletti Reference Cappelletti1971). As Ginsburg (Reference Ginsburg, Whittington, Kelemen and Whittington2008) explains, “constitutional review was seen as an important bulwark against arbitrary governments, and courts were able to draw on this legitimacy in constraining the state” (87).

Of course, judicial review was not a new constitutional invention in the 1940s nor did it “spring new and fully developed from the head of John Marshall” (Cappelletti Reference Cappelletti1971, 25; see also Rakove Reference Rakove1997). Made famous by John Marshall’s opinion for the US Supreme Court in Marbury v. Madison, judicial review was viewed as a natural consequence of Judeo-Christian notions of higher and lower spheres of legal authority: if lower laws come into conflict with some higher sphere of authority, the lower must yield to the higher (Cappelletti Reference Cappelletti1971; Ginsburg Reference Ginsburg, Whittington, Kelemen and Whittington2008). In the century after Marbury, judicial review remained (in Tocqueville’s words) “peculiar to the American magistrate”: few constitutions around the globe explicitly provided courts with the power of judicial review (de Tocqueville Reference de Tocqueville and Reeve1835). But, this changed rapidly in the first half of the twentieth century (Ginsburg Reference Ginsburg, Whittington, Kelemen and Whittington2008). The top panel of Figure 1.1 uses data from the Comparative Constitutions Project to plot the percentage of constitutions establishing judicial review, by year. While less than 20 percent of constitutions provided for judicial review in 1900, around 80 percent of constitutions did so by the century’s end. Today, judicial review has “become a hallmark of the rule of law” such that “[a] democracy without some form of judicial review is considered deficient” (Lutig and Weiler Reference Lutig and Weiler2018, 316).

Figure 1.1

The rise of judicial review and constitutional courts. The top panel plots the percent of constitutions in each year that formally establish judicial review. The middle panel plots the percentage of constitutions that establish a constitutional court. The bottom panel plots the percentage of constitutions that establish each type of constitutional review. The data, which range from 1800 to 2021, come from Elkins and Ginsburg (Reference Elkins and Ginsburg2022).

A variety of theoretical explanations have emerged to explain the rise and proliferation of judicial review, yet central to them all is the sense that judicial review serves as a powerful mechanism of state constraint. In addition to the catastrophic account we describe in the opening pages of this book, federalist accounts emphasize the importance of state constraints across levels and branches of government; judicial review helps to ensure that elites respect complex governmental structures and their constitutionally authorized spheres of authority (e.g., Ackerman Reference Ackerman1997; Shapiro Reference Shapiro, Kenny, Wieseinger and Reitz1999). Ideational accounts prioritize the usefulness of judicial review for the protection of individual rights, suggesting that judicial review might safeguard against human rights violations and threats to citizens’ constitutionally guaranteed rights and liberties (e.g., Cappelletti Reference Cappelletti1971). In the past few decades, a set of strategic explanations has suggested that judicial review is useful not only for citizens but also elites: as those drafting constitutions think ahead, they see judicial review by independent courts as useful insurance in the face of electoral uncertainty to ensure that the constitution’s core values are respected (Ginsburg Reference Ginsburg2003; Hirschl Reference Hirschl2004; Stephenson Reference Stephenson2003). While no single one of these accounts can fully explain the global rise of judicial review (Ginsburg Reference Ginsburg, Whittington, Kelemen and Whittington2008), that it has increased in frequency and expanded in scope is incontrovertible.Footnote ⁴

The second and third panels of Figure 1.1 use data from the Comparative Constitutions Project to illustrate the sharp rise in the percentage of constitutions that establish a specialized constitutional court (middle panel) and the distribution of types of constitutionally endorsed judicial review worldwide. While constitutional courts became increasingly popular throughout the twentieth century, their popularity skyrocketed following the fall of the Berlin Wall in 1989.Footnote ⁵ Today, about half of constitutions worldwide provide for a specialized constitutional court, and judicial review by a centralized constitutional court is much more popular than the decentralized model of judicial review.

How is judicial review exercised in practice? Judicial review can vary on a number of dimensions that define its various modalities.Footnote ⁶ First, scholars distinguish the power of judicial review in the extent to which it is centralized in a single court or constitutional chamber. The “Centralized,” “European,” or “Kelsenian” (after its founder) versions of constitutional review vest the power of judicial review in a specialized constitutional court that is structurally removed from the rest of the judiciary (Harding, Leyland, and Groppi Reference Harding, Leyland and Groppi2008; Horowitz Reference Horowitz2006). Jurisdictional rules for these courts vary, but generally questions concerning the constitutionality of legislation are referred – by ordinary court judges or litigants – to a specialized constitutional court that is situated apart from the formal judicial hierarchy and is empowered to make a final ruling on the constitutionality of legislation, executive actions, or governmental proposals. This form of judicial review was first used in Austria and has been adopted in countries like Germany, Italy, and Spain; variants abound throughout the democratizing world. The alternative modality, often called a “decentralized” or “American” model, distributes the power of judicial review diffusely throughout the judicial hierarchy. Any judge confronted with a statute or action that violates the constitution is empowered to use judicial review to strike the statute as unconstitutional. This decentralized form of judicial review is found throughout the separation of powers systems of Latin America, as well as many British colonies in the Western Hemisphere, Africa, and Southeast Asia.

In addition to variation in who can conduct judicial review, countries also vary according to when laws can be reviewed.Footnote ⁷ On the one hand, courts like the US Supreme Court exclusively exercise “concrete” judicial review, only deciding actual cases or controversies that come about after a law has been enacted and when the legal or constitutional controversy has been challenged in a specific instance or case. In other systems, constitutional courts are empowered to exercise “abstract” judicial review, which allows courts to decide on the constitutionality of laws or administrative actions without the need for a concrete case or harm to litigants. Notably, this form of judicial review has the potential, in some systems, to take place prior to promulgation or enactment of a challenged statute or regulation, allowing the court to serve as an ancillary legislative chamber as opposed to an adjudicatory body. Data from the Comparative Constitutions Project documents that, as of 2021, a majority of constitutions do not specify at what stage of the legislative process legislation is reviewed for its constitutionality. But, of those constitutions that specify, 24 percent allow for review pre-promulgation (ex ante review), 35 percent allow for ex post review, and 42 percent allow for constitutional review at either stage (Elkins and Ginsburg Reference Elkins and Ginsburg2022).

Judicial review also varies in the scope of a constitutional or judicial ruling, a feature which often covaries with the timing and centralization of judicial review. The (often abstract review) decisions rendered by centralized constitutional authorities often carry with them erga omnes effects, meaning the decisions are binding to any and all parties involved in a constitutional controversy, whether they are parties to a particular case or not, and direct harm need not be empirically substantiated. Where judicial review is exercised with reference to concrete cases, judicial decisions are said to be binding inter partes, such that they are only for the plaintiffs litigating in a particular case. The exception to this general rule is when the norm of stare decisis applies, which implies that future judicial decision-making is bound to adhere to the legal standards set out in a particular case or settlement. Such is the case with Supreme Court decision-making in the United States, where the pinnacle court’s adjudications are viewed as binding and informative for all future judicial decisions throughout the judicial hierarchy.

Scholars have observed that this dramatic expansion of judicial review and constitutional authority has coincided with the rise of rights-related litigation and the increased involvement of judicial authorities in all manner of policymaking arenas (Bricker Reference Bricker2016; Hirschl Reference Hirschl, Whittington, Kelemen and Caldeira2008; Vallinder and Tate Reference Vallinder and Tate1995). Not only has the formal authority and autonomy of high courts expanded (Brinks and Blass Reference Brinks and Blass2018; Hirschl Reference Hirschl, Epstein, Grendstad, Šadl and Weinshall2024), so too has the constitutionalization of the rights of citizens, creating both the opportunity and the venue for expanded claims of constitutionality (Botero Reference Botero2023; Epp Reference Epp1998; Hirschl Reference Hirschl2004). Courts and the judicial authorities that operate within them have been featured prominently in many of these accounts, sometimes playing the protagonists to rights-claimants, while in other instances revealing pronounced reluctance to involve themselves in such questions or controversies (Botero, Brinks, and Gonzalez-Ocantos Reference Botero, Brinks and Gonzalez-Ocantos2022; Bricker Reference Bricker2016).

In short, the presence and exercise of judicial review has proliferated over the course of the past century, in all parts of the globe. States worldwide have put their faith in independent courts as tools to police the boundaries of state authority, ensuring that executives and legislatures do not overstep their constitutionally authorized powers. But, has this worked? Theorizing and identifying the conditions under which the use of judicial review by constitutional courts might be an effective tool of state constraint is the aim to which we now turn.

Understanding Judicial Efficacy

Answering our research question – when are courts effective tools of state constraint? – requires us to clarify what we mean by judicial efficacy. At first glance, the idea that constitutional courts might constrain the state seems obvious. After all, that governments must adhere to the rules that structure the political process is a commonsense foundation of the rule of law. Constitutions and legal statutes represent a stated commitment to designated powers and formalized procedures. They delineate the process by which preferences become policy, the prerequisites for ambitious citizens to enter the class of political elites, and the process by which disputes are adjudicated when the interests of actors with legitimate claims come into conflict. Irrespective of one’s power or prestige, that both governments and common citizens are equally bound by the law is a premise which has long stood at the foundation of democratic systems of governance. Judicial review, then, is a tool that constitutions can use to ensure the rule of law is respected.

Moreover, scholars frequently highlight the global expansion of judicial power, noting that many governments today represent juristocracy or “rule by judges” (e.g., Hirschl Reference Hirschl2004, Reference Hirschl, Whittington, Kelemen and Caldeira2008). In many cases, it is now unelected judges rather than elected representatives that have the final say on many of the pressing political and policy issues affecting citizens and governments around the globe. These accounts suggest that courts – particularly those formally empowered to exercise judicial review – have become so politically formidable that they have the potential to be the most influential branch of government.

In practice, achieving this ideal is easier said than done. Compliance and enforcement of the rule of law are challenges that every political regime must face. For reasons ranging from resource constraints to ideological judgments, not all legal violations face commensurate legal consequences. These challenges only increase in scope and difficulty when the person or entity pushing the boundaries of the law is vested with political power. The practicalities of trying or punishing elected officials for illegal actions – the traditional consequences for breaking the law – are complex, especially if those officials are to be investigated or tried while they are in office. In many places, elected officials are protected from prosecution for the duration of time they serve in office, incentivizing efforts to sustain their control on power. If those in power feel that they are able to defy the law with impunity, abuse of power may run rampant, and state constraint may prove impossible. James Madison, in Federalist Paper No. 51, summarized this challenge well: “In framing a government which is to be administered by men over men, the great difficulty lies in this: you must first enable the government to control the governed; and in the next place oblige it to control itself” (emphasis added).

There are good reasons to be skeptical that constitutional courts will necessarily be an automatic agent of state constraint. While courts worldwide have been imbued with the power of judicial review, they are – paradoxically but indisputably – incredibly weak. Unlike executives who command armies or legislators who can oversee and discipline the bureaucrats who implement the laws they pass, courts must depend on others to implement their policies. As Alexander Hamilton famously wrote in Federalist #78 (Hamilton, Madison, and Jay 1787/Reference Hamilton, Madison and Jay1788):

This lack of implementation authority and the accompanying threat of noncompliance presents a fundamental challenge for judicial efficacy: if courts speak but no one listens, they are ineffective.

Given the challenges to compliance and implementation, purely legal solutions to legal violations – in other words, the mere establishment of judicial review – are insufficient to ensure a stable system of the rule of law. However, other potential consequences exist. For centuries, societies have supplemented legal consequences for illegal actions with political consequences:

Where elected officials know they are likely to face robust political consequences for illegal action, they may exercise self-constraint not because they fear legal repercussions, but rather because they know illegal actions will undermine their own political self-interest. Conversely, if incumbents are sufficiently confident they will face no real political consequences for crossing the line of constitutional or statutory law, they might have few incentives to adhere to the written rule of law. Perhaps because they have co-opted courts, stacked the deck of institutional players, or believe the public will overlook the transgression, incumbents in such a position may see no reason to refrain from using their office to advance their own political interests.

Our argument in this book is that judicial review can provide both legal and political penalties for incumbents who violate the rule of law, thereby helping to constrain the state. Courts with the power of judicial review are, almost by definition, able to levy legal penalties on incumbents who violate the rule of law. But critically, not all courts have the ability to create political damages for incumbents.

This latter idea forms our definition of judicial efficacy: courts are effective when they are able to create political penalties for elites who fail to abide by the constitutional limits on their authority.Footnote ⁸ When courts strike down a law through the power of judicial review, they are merely putting their thoughts about the congruence between a policy and a constitution down on paper. Judicial decisions are neither self-enforcing nor self-implementing. For judicial review to be effective, judicial decisions must have meaningful, impactful consequences. It is this political force – in addition to the legal force – of decisions that defines judicial efficacy. Effective courts are able to inflict both legal and political penalties on incumbents. When those consequences are diffuse or nonexistent, a court lacks efficacy.

Before moving forward, it is helpful to compare our definition of judicial efficacy with those others have suggested. This term has been widely used, albeit with varying definitions. Stone Sweet (Reference Stone Sweet2012) provides a procedural conceptualization of efficacy:

Harding, Leyland, and Groppi (Reference Harding, Leyland and Groppi2008) provide a more normative conceptualization: “whether the court’s interventions are consistent with the norms set out in the constitution and whether these norms are consistent with principles of ‘good governance’” (18).Footnote ¹⁰ And, on a more empirical front, Magalhães and Garoupa (Reference Magalhães and Garoupa2020) equate efficacy with efficiency, using a measure of case processing time.

None of these definitions serve our purpose well. Stone Sweet’s definition centers litigants in their decisions to bring disputes to courts and accept judicial rulings. While we agree that acceptance of rulings is an important outcome, we argue that efficacy is more about responses to decisions than a willingness to use the legal system in the first place.Footnote ¹¹ Likewise, our primary interest is in the ability of judicial review to promote state constraint, so Harding, Leyland, and Groppi’s normative definition is not particularly appropriate for our purposes. Moreover, their definition focuses more on the propriety of a judicial opinion than any effects it might have on litigants or implementing populations. And, while we appreciate Magalhães and Garoupa’s (Reference Magalhães and Garoupa2020) more empirical approach, we take a broader view of efficacy: it matters not just how quickly courts decide cases but whether those decisions “matter.”

Other conceptualizations of efficacy relate the concept directly to judicial independence. Fariss and Dancy (Reference Fariss and Dancy2017) suggest efficacy is synonymous with de facto judicial independence, although Ríos-Figueroa (Reference Ríos-Figueroa2007) disagrees:

Judicial independence and efficacy may be related, but they are not synonymous. As Ríos-Figueroa (Reference Ríos-Figueroa2007) writes, judicial independence may enhance judicial efficacy (a hypothesis we test repeatedly throughout this book), but judicial independence does not necessarily imply the presence of an efficacious court. Independence is, in a broad sense, the freedom of judges to decide cases as they see fit. Efficacy – as we explain in further detail below – relates to the consequences of those decisions: are there penalties for ignoring courts?Footnote ¹²

Still more conceptualizations directly link efficacy and implementation (e.g., Clark Reference Clark2010, 67). Epstein and Knight (Reference Epstein, Knight, Delaney and Dixon2018) write that “efficacious decisions” are “those that relevant external actors will respect and with which they will comply” (272) and Vanberg (Reference Vanberg and Andeweg2020) argues that “Courts are influential if executive branch officials cannot easily evade decisions or refuse to comply with them” (570). Ríos-Figueroa (Reference Ríos-Figueroa2007) defines an effective judiciary “as one that is able to rule against the interests of power holders without being systematically overruled, challenged with noncompliance, or punished with more aggressive policies, such as court packing, impeachment of judges, or budgetary cuts” (31–2).

Our conceptualization of efficacy is closer to these definitions. At its core, efficacy is about the consequences that judicial decisions bring to bear outside of the courtroom, and nonimplementation of a judicial decision is an important indicator that a court may be lacking in efficacy. But, for our purposes, while nonimplementation is one possible way that a court might lack influence, it is not necessarily a sign that a court lacks efficacy. Courts may strategically enable noncompliance (e.g., Staton, Reenock, and Holsinger Reference Staton, Reenock and Holsinger2022; Staton and Vanberg Reference Staton and Vanberg2008). Moreover, as executives respond to judicial decisions with an expectation regarding the presence and magnitude of a penalty for disregarding a court, there is a potential for miscalculations resulting in nonimplementation that is subsequently met with an unanticipated public outcry and corresponding political penalty (Vanberg Reference Vanberg2000). Conversely, that executives abide by a court’s decision does not necessarily imply judicial efficacy because governments might comply for strategic reasons that are unrelated to the threat of a noncompliance penalty (Whittington Reference Whittington2005). As a result, observing judicial efficacy is not as straightforward as observing (non)implementation, and treating the two as synonymous risks misidentifying judicial (in)efficacy. For this reason, our conception of efficacy is broader than a single-minded focus on nonimplementation and instead takes a broad view of the political penalties associated with challenging an efficacious court.

It is important to note here that our conceptualization of efficacy is fundamentally negative: courts with efficacy are those who can successfully impose political penalties on incumbents. But there is another, more expansive, conceptualization of efficacy that would envision a court’s ability to fully legitimize executive actions (e.g., Johnson and Whittington Reference Johnson and Whittington2018). Dating back at least to Dahl’s (Reference Dahl1957) suggestion that “[t]he main task of the Court is to confer legitimacy on the fundamental policies of the successful coalition,” dozens of studies have sought to understand the conditions under which citizens might change their views of policies in response to a judicial decision (294). By this account, a judicial decision in favor of a policy might inspire confidence in the government’s action and thereby foster acceptance from an otherwise suspicious or unsupportive public. In this way, “effective” courts might be able to lessen the political penalties of rule of law violations by ruling in an incumbent’s favor, thus rallying public support for an incumbent’s policy.

This suggestion that courts might be able to shape public opinion has important implications. In particular, it makes the prospect of court capture even more tantalizing. Not only does such capture lower the risk of unfavorable decisions and thus create increased opportunities to entrench preferred policies, but it might also provide incumbents with a tool to shape public opinion toward their preferred policies. If courts bring with their decisions enhanced public acquiescence or acceptance on controversial policies, then deck stacking or court co-optation is not just a matter of skirting accountability. Institutional capture could actually bolster regime support.

We are profoundly skeptical that courts, including even the most independent ones, have this power. As we elaborate in Chapter 2 and go on to demonstrate throughout this book, we see limited theoretical reasoning and no empirical evidence to support Dahl’s suggestion that courts might legitimate governmental policy. Instead our findings show that following a court’s explicit endorsement of a policy (which we term “clearance”), citizens accept the policy just as they would have had the court not acted at all. This asymmetry – that courts’ decisions against the government can elicit a response from citizens while declaring a policy constitutional does not – reflects the centrality of state constraint as a fundamental function of courts and judicial review.

Political Penalties for Rule of Law Violations

We have suggested that courts are effective when they can impose political penalties for rule of law violations. What sorts of political penalties exist? In modern democracies, executives may face an array of political penalties for their violation of the law. Transgressing the written rule of the law may be costly in terms of elite bargaining, as a demonstrated willingness to abandon the “rules of the game” may undermine trust that bargaining is occurring in good faith. Alternatively, it may be that the citizens themselves can impose penalties on the government by withdrawing their electoral or political support. The credible threat of this punishment, in theory, will incentivize “good” behavior. These two types of political ramifications correspond to two different explanations for the emergence and perpetuation of the rule of law, which we address in turn.

Public Evaluations of Executive Action

We are far from the first to suggest that the public might impose political penalties for rule of law violations. Indeed, a rich literature on state constraint has long emphasized the importance of cultural values, particularly democratic norms and values, for sustaining the rule of law and democratic governance (Almond and Verba Reference Almond and Verba1963; Claassen Reference Claassen2020; Easton Reference Easton1953; Lipset Reference Lipset1959; Putnam Reference Putnam1993). Likewise, another expansive strand of research has focused on the capacity of institutions to structure political outcomes (Huber Reference Huber1996; North Reference North1990; Tsebelis Reference Tsebelis2011), including those related to core democratic principles like accountability (Tavits Reference Tavits2007) and responsiveness (Powell Reference Powell2004), as well as citizens’ attachment to the state (Elkins and Sides Reference Elkins and Sides2007) and ultimately the survival of constitutions and democracy itself (Elkins Reference Elkins2010; Elkins, Ginsburg, and Melton Reference Elkins, Ginsburg and Melton2009; Linz Reference Linz1990; Maeda Reference Maeda2010). Our approach here combines insights from both accounts to evaluate the interaction between system-level institutional features – for us, judicial independence – and individual-level attitudes, specifically support for the rule of law.

Studies of the public’s response to executive unilateral action in the United States provide a useful point of comparison (e.g., Braman Reference Braman2023; Christenson and Kriner Reference Christenson and Kriner2020b; Reeves and Rogowski Reference Reeves and Rogowski2022a). Like us, scholars working in this vein are seeking to understand the conditions under which the public might serve as an efficacious check on executive action. As Christenson and Kriner (Reference Christenson and Kriner2020b, 6) explain, “the president’s standing among the public is perhaps the most ubiquitous and salient measure of a president’s political capital and thus ability to advance his or her agenda in Washington.” As the public withdraws its support from the president, it is difficult for the president to accomplish his or her policy goals. In contrast, strong public backing translates into effective political capital for policy-minded executives (Barrett and Eshbaugh-Soha Reference Barrett and Eshbaugh-Soha2007; Canes-Wrone and De Marchi Reference Canes-Wrone and De Marchi2002).

From this literature, two points are particularly relevant for our purposes. The first concerns how the public evaluates unilateral executive actions. On the one hand, Reeves and Rogowski (Reference Reeves and Rogowski2016) describe that the public generally disapproves of presidential unilateral action, with variation in evaluations of these executive actions inexorably linked to the public’s commitment to the rule of law (see also Reeves and Rogowski Reference Reeves and Rogowski2022a). On the other hand, Christenson and Kriner (Reference Christenson and Kriner2017a) contend that concerns such as partisanship are the primary driving forces behind the public’s responses to executive unilateral action (see also Christenson and Kriner Reference Christenson and Kriner2020b). Relatedly, Braman (Reference Braman2021) finds that approval of the executive plays an outsized role when the public evaluates executive action while constitutional considerations – here, as judged by “experts” – have no effect on respondents’ policy support (see also Braman Reference Braman2016, Reference Braman2023).

Yet these studies have important differences from our own. For instance, Reeves and Rogowski rely on generic questions about particular types of unilateral actions, while Christenson and Kriner, as well as Braman, deploy questions that tap reactions to pressing real-world controversies. And, although all three sets of authors acknowledge the potential for a partisanship-versus-democratic values debate, they do not test these competing considerations head-to-head. Our ability to concisely weigh these contrasting claims is further complicated by these authors’ near-exclusive focus on the public’s reaction to executive unilateral authority in United States (but see Reeves and Rogowski Reference Reeves and Rogowski2023). This limitation leaves us less sure about how other citizenries respond to unilateral executive actions where these sorts of actions are more commonplace, such as contexts where executives have broader constitutional mandates to wield this particular sort of power (but see Chu and Williamson Reference Chu and Williamson2025). Although this lack of evidence leaves us agnostic about which account presents the more persuasive set of evidence about the factors shaping the public’s response to executive action, it sets the stage for these dueling considerations – support for the rule of law and partisanship – to play a prominent role in our investigation.

Second, Christenson and Kriner’s studies investigate the extent to which legislatures and courts might affect the public’s response to executive action. Interestingly, though, their research designs focus on extra-institutional actions rather than the formal system of checks and balances. They write: “Even when they cannot block or overturn a unilateral action, other political actors remain relevant through their special capacity to mobilize the public and bring popular pressure to bear on the White House” (Christenson and Kriner Reference Christenson and Kriner2020b, 7). They demonstrate that both congressional criticism of an executive action and the threat of litigation both detract from the public’s support for executive actions. (Christenson and Kriner Reference Christenson and Kriner2017c, Reference Christenson and Kriner2019). As they conclude in one study, “[p]ublic opinion – not formal checks by Congress and the courts – serves as the primary check on the unilateral executive” (Christenson and Kriner Reference Christenson and Kriner2020b, 8).

If strategic political communication by legislators or potential litigants can shape the public’s response to executive action, then it stands to reason that democratic institutions themselves, especially courts, might play a particularly important role in channeling public opinion as their decisions provide credible signals to their constituents that an executive is overreaching. After all, there is a chasm of difference between an interest group saying they might sue the executive or a legislator taking to the lectern to disparage a policy they do not like, and a pinnacle court summarily striking down an executive action. When courts exercise their power of judicial review, they harness both a powerful legal tool and the trappings of judicial office to inform the public about whether an executive is overstepping their constitutional authority. This possibility – left unaddressed in existing studies – forms the foundation for this book.

Other Theories of Judicial Efficacy

How have others thought about the conditions under which courts become powerful and effective partners in governance? We contribute to a rich set of studies that have sought to understand the conditions under which powerful judiciaries emerge and persist.Footnote ¹⁹ The classic separation of powers models position courts as an additional veto player in the policymaking process whose assent is required to enact or implement policy (Ferejohn and Shipan Reference Ferejohn and Shipan1990; Tsebelis Reference Tsebelis2011). Subsequent innovations on these models underscore how the mere presence of judicial review can shift the strategic landscape of policy-motivated incumbents and change the scope of viable policy that might reasonably displace a status quo (Shipan Reference Shipan2000). Although an instructive approach to mapping judicial review’s effect on the scope of bargains struck in the policymaking process, these veto player models make judicial efficacy a fait accompli, as questions of compliance are set aside and courts’ decisions are presumed to be binding.

Perhaps the most prominent of these alternative theories of judicial efficacy emphasizes judicial legitimacy and the public’s support for courts. As Gibson, Caldeira, and Baird (Reference Gibson, Caldeira and Baird1998) write, courts that lack legitimacy can “find it difficult to serve as effective and consequential partners in governance” (343). When citizens hold a court in high regard and expect officials to uphold the integrity of the judiciary by faithfully implementing judicial rulings, the threat of punishment at the ballot box for noncompliance can compel officials to comply with decisions, including those with which they disagree (Krehbiel Reference Krehbiel2021c; Staton Reference Staton2004; Vanberg Reference Vanberg2001). This electoral threat, coupled with public awareness of a government’s failure to comply, can exert considerable influence on the bounds of judicial authority (but see Driscoll and Nelson Reference Driscoll and Nelson2023a, Reference Driscoll and Nelson2023b; Nelson and Driscoll Reference Nelson and Driscoll2023). The public support theories of judicial efficacy and power suggest that courts need to be careful stewards of their public standing: without it, there is no reason for legislators or executives to listen to their decisions and obey their opinions. By this logic, courts might be expected to exhibit self-restraint in the face of declining public standing (Clark Reference Clark2009).

An empirical implication of these legitimacy-based accounts is that they envision broadly supportive courts as having the power to impose both political penalties on incumbents for rule of law violations but also the ability to legitimate constitutionally suspect policies, thereby weakening constraints on the state. Empirically, the evidence that courts have this power to legitimize is both mixed and conflicting. Some suggest that courts can lend an air of authorization to otherwise suspect policies (Bartels and Mutz Reference Bartels and Mutz2009; Clawson, Kegler, and Waltenburg Reference Clawson, Kegler and Waltenburg2001; Gibson, Caldeira, and Spence Reference Gibson, Caldeira and Spence2005), while other studies suggest that judicial decisions polarize public sentiment (Adams-Cohen Reference Adams-Cohen2020; Clark et al. Reference Clark, Staton, Wang and Agichtein2018; Franklin and Kosaki Reference Franklin and Kosaki1989; Woodson Reference Woodson2019). And an even larger set of studies suggests that a court’s ability to change public opinion is either conditional or limited (Bishin et al. Reference Bishin, Hayes, Incantalupo and Smith2021; Christenson and Glick Reference Christenson and Glick2015b; Fontana and Krewson Reference Fontana and Krewson2023; Stoutenborough, Haider-Markel, and Allen Reference Stoutenborough, Haider-Markel and Allen2006; Zilis Reference Zilis2015).Footnote ²⁰ Nearly all of these studies focus on the ability of a single court – the US Supreme Court – to affect public attitudes (but see Woodson Reference Woodson2019; Baird and Javeline Reference Baird and Javeline2007; Bentsen Reference Bentsen2019; Kreitzer, Hamilton, and Tolbert Reference Kreitzer, Hamilton and Tolbert2014). As a result, we know little about how different types of courts, political contexts, or other factors condition the ability of courts to shape public opinion. Further, these studies tend to focus on changing citizens’ minds on particular issues, rather than on the overarching issue of state constraint: to what extent can judicial decisions shape citizens’ attitudes toward the policymakers whose decisions the court is reviewing? Or, put differently, can courts shape public opinion in ways that can constrain or embolden executives?

A second set of theories, known as nonmajoritarian accounts, suggests that compliance with judicial decisions – and allowing a powerful judiciary to emerge – provides direct benefits to policymakers. By this logic, many issues on which executives or legislatures must make policy are unsavory for elected officials to act upon because the issue divides their constituents (e.g., many social policies). In these situations, a strong judiciary can provide political cover to other policymakers by providing the final say on issues where legislators or executives may prefer to not act (Graber Reference Graber1993; Rogers Reference Rogers2001; Stephenson Reference Stephenson2004; Whittington Reference Whittington2005). As Graber (Reference Graber1993) puts it, policymakers “encourage or tacitly support judicial policymaking both as a means of avoiding political responsibility for making tough decisions and as a means of pursuing controversial policy goals that they cannot publicly advance through open legislative and electoral politics” (37).

These nonmajoritarian theories imply that courts are powerful because of the distribution of public support for other branches of government. Thus, courts derive their power from other politicians’ strategic calculi vis-à-vis the electorate: they provide a useful way for incumbents to avoid or deflect public ire or evade direct political accountability entirely. Moreover, the very political disagreements that make courts useful foils for incumbents also make it difficult for citizens to coordinate a campaign against the court to reduce its power or independence, further emphasizing their usefulness to incumbents on controversial issues.

A final class of explanations suggests that strong judiciaries provide insurance for policymakers who know they may someday find themselves out of power (Boudreaux and Pritchard Reference Boudreaux and Pritchard1994; Ginsburg Reference Ginsburg2003; Landes and Posner Reference Landes and Posner1975; Ramseyer Reference Ramseyer1994; Stephenson Reference Stephenson2003). These theories suggest that judicial efficacy is tied to political competition. When competition between political factions in a country is high and partisan control of the elected branches of government is variable, those currently in power can benefit from independent courts that are less likely to overturn their policies when the other faction comes into power. By this logic, incumbents may tolerate a sometimes pesky independent court in the short term, knowing they will benefit from its protection when they are in the opposition over the longer term.

Similar to legitimacy and nonmajoritarian models, insurance theories make an implicit connection between the public’s electoral choices and the power of constitutional courts. Judicial efficacy in these accounts is a function of the relative distribution of support for political parties in the electorate as politically strong and judicially unfavored parties will promote judicial deference while politically weak and judicially favored parties will advocate for judicial independence. These accounts highlight two constraints on the power of judicial review. First, they suggest that if the judiciary is too demonstrably favorable to one party or the other, it will lose the support of both (Stephenson Reference Stephenson2003). Second, they indicate that if a dominant party emerges in the electoral landscape, it may be more willing to take actions that weaken the judicial branch (Ramseyer Reference Ramseyer1994). In this way, judicial power is inexorably tied to partisan electoral politics and at heart is a question of electoral competition (Ferejohn Reference Ferejohn1998).

While each of these three theories motivate ebbs and flows in judicial efficacy through different mechanisms, key to all three of these accounts is the relationship between courts and the public. While some theories – especially the legitimacy-based theories – make this connection explicitly and others – the informational and insurance theories in particular – do so to a lesser extent, all three alternative accounts of judicial efficacy suggest that judicial power depends on the public, particularly as a nexus that conditions the judiciary’s relationship to incumbents. As Clark and Vanberg (Reference Clark, Vanberg, Jenkins and Rubin2022) write, “The most important factor that explains [the expansion of the judicial role] is the desire by powerful interests outside of the formal machinery of government – most obviously, citizens at large – to subject the political process to rules and constraints.” And while we share a common focus for our interest in the public’s involvement in state constraint, our theoretical account advances an alternative mechanism, under a more clearly defined scope condition, as to why courts might be effective participants in the business of state constraint.

These theories generally do not address the role of courts with respect to state constraint. The legitimacy-focused theories – taken to their extreme – suggest that a broadly supported judiciary may be able to create penalties for noncompliance but may pose a new threat to state constraint – juristocracy – by swaying the public toward the court’s position on the salient issues it decides. And the nonmajoritarian and insurance theories focus more on the benefits to incumbents that come from the establishment of powerful and independent courts, rather than the consequences incumbents may face for defying the courts. By contrast, we look to courts and their associated power of judicial review as they exist in the world, with varying levels of judicial independence and constituents who vary in their reverence for the rule of law. In doing so, we ask whether judicial review is able to serve the role so often ascribed to it with the goal of assessing how – and under what conditions – courts can use judicial review to live up to their lofty function as an institutional guardrail to uphold state constraint.

As we elaborate in more detail in Chapter 2, we see both theoretical and empirical weaknesses to the legitimacy account. Theoretically, if courts are tools of state constraint, then they should impose penalties for violations of the constitutional order but not facilitate incumbents’ rule of law violations. Our theory ascribes this more limited role to effective courts, one which allows judicial institutions to be critical mechanisms of state constraint, but whose institutional capacity does not include the ability to legitimate policy.

As to the nonmajoritarian accounts, our own theoretical model envisions a broader foundation of possible judicial influence. Courts may be influential not only on those controversial issues about which the public is divided or for which courts serve as convenient foils for incumbents to avoid electoral blame. Instead, courts should be able to create meaningful political penalties for rule of law violations, even in the face of popular incumbents who choose to take actions that violate legal dictates. For this reason, we devote a good deal of attention throughout this book to the potential for shared partisan ties to weaken (or completely hamper) judicial efficacy. Contra the nonmajoritarian account, we refocus the question of state constraint away from how it might benefit incumbents, and back to how it might contain them. And, much like the insurance models, we appreciate the context in which judicial review occurs and vary it accordingly in our research design. That said, we reorient the focus here from electoral competition to center more squarely on courts, the public and judicial review.

Our Argument

Traditional accounts of judicial review emphasize its role in shaping legislation throughout the policymaking process, either with the idea that courts are veto players (Epstein and Knight Reference Epstein and Knight1998; Krehbiel Reference Krehbiel1998; Tsebelis Reference Tsebelis2011) or the idea that the threat of judicial review leads legislators to adjust legislation during the policymaking process (a concept called autolimitation) (e.g., Vanberg Reference Vanberg2001). These accounts of judicial review focus on intraelite conflict, emphasizing courts’ coequal role in the policymaking process and leaving aside the informational role that courts might play to the public.

But many accounts of judicial review view courts as fundamentally weak when it comes to fulfilling such roles. Focusing on the limited ability of courts to ensure the implementation of their decisions, political scientists have increasingly come to view the presence of judicial efficacy as the puzzle to be explained rather than the norm to be expected. This has led scholars to suggest that courts might need to behave strategically to avoid confrontation with executives (Clark Reference Clark2010; Iaryczower, Spiller, and Tommasi Reference Iaryczower, Spiller and Tommasi2002; Vanberg Reference Vanberg2005). Other accounts have expanded on this logic by contending that courts strategically try to bolster their own public standing in order to make their judicial review more efficacious in the face of political constraints (e.g., Krehbiel Reference Krehbiel2016; Staton Reference Staton2010). Throughout such accounts, scholars underscore the inherent weakness of judicial review that results from a lack of direct means of political enforcement for court decisions.

We emphasize its strengths. We take a step back, focusing on how the nature of constitutional review as an institutional tool can empower courts to affect public sentiment and constrain executives. We argue and demonstrate that, through the use of judicial review, courts help citizens solve a fundamental collective action and monitoring problems by removing ambiguity about the legality of an executive’s action and giving the public a clear indication about the action’s constitutional propriety. When independent courts tell citizens that an executive has transgressed the constitutional order, we expect citizens to withdraw acceptance from the executive’s action. To test this argument, we draw on a series of original and harmonized survey experiments fielded in four countries (the United States, Germany, Hungary, and Poland), countries we selected for their diverging levels of judicial independence.Footnote ²¹

We find that high levels of judicial independence are a prerequisite to judicial efficacy: courts with low levels of judicial independence lack the credibility necessary to shape public acceptance. Moreover, those citizens who profess a high level of support for the rule of law react more negatively to executive actions that contravene independent courts than their counterparts with weak commitments to the rule of law. Strikingly, we find that independent courts’ ability to activate public opposition to controversial policies holds even in the face of partisanship. Citizens seem to care more that executives are playing by the rules than that their favored executive gets her way.

Independent judicial review can thus mobilize the public to act as a state constraint under the right conditions: courts must be independent and the public must be sufficiently supportive of the rule of law. Critically however, judicial decisions only affect public opinion when the court strikes down policies, meaning that the ability of courts to move public opinion in favor of an incumbent’s policy (and thereby to weaken constraints on the state) is limited. Even where courts are independent and powerful, and even where the public is receptive to high courts’ decisions, the efficacy of judicial review is asymmetric in that courts can only affect citizens’ attitudes through decisions stating the executive has breached the rule of law.

The picture of judicial efficacy that emerges from our argument and analysis is both robust and limited. That judicial independence is a prerequisite to efficacy means that many constitutional courts – especially in contexts where judicial independence is precarious – may be limited in their ability to serve as a successful check on executive authority. Moreover, that the penalty for noncompliance is concentrated among citizens who attach a great deal of weight to the rule of law suggests that de jure independence, on its own, is not enough to guarantee that constitutional courts are effective tools of state constraint. Rather, courts must be independent and situated in political systems with citizens who have deeply held respect for the importance of the rule of law. Furthermore, even in polarized societies, partisanship seems to pose only a limited threat to the ability of independent courts to constrain the state. Finally, despite decades of scholarship yielding mixed and conflicting findings, we present a theoretical account – backed up by empirical evidence that is consistent across multiple experiments and countries – to explain why courts are not effective agents of legitimation. This, we argue, is normatively good: incumbents that capture courts may remove a hurdle in the policymaking process, but they will not reap an additional reward, as courts cannot simply bend public opinion to their will.

Outline of This Book

Chapter 2 presents the theory we have just previewed in more detail. Even where public consensus exists regarding the appropriate bounds of constitutional action, the public’s capacity to credibly punish executive overreach can be significantly hampered by citizens’ lack of information about possible transgressions and the need for coordination to impose meaningful political penalties (Weingast Reference Weingast1997). Courts are key to overcoming these obstacles: under the right conditions, they are uniquely positioned to alert the public of governmental transgressions and to transform the public’s support for the rule of law into a guardrail against executive overreach. Here, we explain why judicial review by independent courts, which the public regards as high credibility sources, can provide citizens with reliable and trustworthy information about their executive’s behavior vis-à-vis constitutional norms. By contrast, courts with low levels of judicial independence are impotent: their decisions are not credible enough to matter. We further expect the rulings of independent courts to be most pursuasive to citizens who have a high level of support for the rule of law and to be effective even in the face of stark partisan polarization.

Chapter 3 presents our research design. After beginning the chapter with a brief discussion on the advantage of our comparative research design, we accomplish four tasks in the chapter. First, in recognition of our theory’s emphasis on judicial independence, we select four cases – the United States, Germany, Hungary, and Poland – that give us vital variation in this respect but share important political, legal, and socio-economic characteristics. To further reinforce the appropriateness of our selected cases within the context of our theory, we use survey data to demonstrate that this variation in judicial independence is observed by citizens in these countries, just as it is by experts. Second, the chapter establishes the inferential role the COVID-19 pandemic plays in our analyses. In particular, we emphasize that the global pandemic presented a unique and fleeting opportunity to test citizens’ reactions to rule-of-law violations as a result of the real governmental overreach it produced that were similar in every country around the world. Third, we discuss the benefits of using survey experiments for a study like ours, and conclude with a discussion of the strengths and weaknesses of our research design. Finally, we contextualize our quartet of cases by provide background information on their general political characteristics, the institutional characteristics of their constitutional courts, and their respective handling of the pandemic.

The public’s support for the rule of law is a key democratic value and a cornerstone concept in our book. We therefore devote Chapter 4 to providing the most systematic analysis to date of its measurement, correlates, and stability. In the chapter, we draw on original survey data to validate an updated measure of the public’s support for the rule of law. We demonstrate that support for the rule of law is highest among the most politically sophisticated and those with strong support for democratic values. Further, we illustrate the predictive validity of our measure through the analysis of a survey experiment. We then draw upon thousands of survey responses in the United States and an original six-wave survey panel in Germany to demonstrate the stability over time of the public’s support for the rule of law – at both the aggregate and individual levels – even in the face of a myriad of potential challenges.

Chapters 5 and 6 present the core tests of our theory. In the former, we rely upon two experiments to demonstrate that the public withdraws acceptance of policies implemented through contravention – in other words, over the objection of a court – but only if that court has a high level of judicial independence. In so doing, we causally identify the effect of a court’s decision against the government on public acceptance of the executive’s rule of law violation. We show that contravention of an independent court causes the public to withhold its acceptance, relative to a situation where there was no judicial review. But, if executives contravene a low independence court, it is as if the court had not acted: there is no difference in the public’s level of acceptance. Third, we find no evidence in any of our quartet of countries that judicial approval affects the public’s acceptance of an executive’s policy. Contrary to fears that citizens may blindly follow courts and adjust their opinions based on the court’s verdict, even respondents in the United States and Germany accepted policies endorsed by their constitutional court as constitutional no differently than they would have if the policy was enacted without any action by the judicial branch.

In Chapter 6, we examine the effects of judicial review across citizens to demonstrate that the public’s support for the rule of law lies at the heart of judicial efficacy. We find that, where courts enjoy high levels of judicial independence, their rulings’ efficacy is amplified among citizens who have a strong regard for the rule of law. However, when citizens have low levels of support for the rule of law, the effect of a court’s ruling is muted. For courts that lack judicial independence, even those citizens who hold the rule of law in the highest regard are unaffected by a court’s determination that that an executive’s behavior is unconstitutional. This implies that without credibility, these courts lack efficacy even for those citizens who are most predisposed to be favorable and responsive to them. And, regardless of the level of judicial independence, we find no evidence that even those most committed to the rule of law increase their level of acceptance after a court endorses a policy.

We also consider how the efficacy of judicial review varies based on the public’s approval of the executive whose policy the court reviews. Here, we again find that only independent courts are able to make rulings that impact the public’s response, although the variation in this effect is somewhat surprising. Echoing Reeves and Rogowski (Reference Reeves and Rogowski2022a), we find that the public constraint on executives comes from their supporters, not their opponents. In other words, the penalty for implementing a policy by contravening a court is strongest among those citizens who hold the executive in high regard. Among those who dislike the executive, acceptance of the policy is unmoved by the manner in which the executive enacts it. These findings point to an important implication: political sympathy for the executive, here in the form of approval and copartisanship, may not necessarily be the Achilles heel of judicial efficacy it is often portrayed to be.

The second pair of empirical chapters, Chapters 7 and 8, build on these analyses by giving careful attention to a real and pernicious threat to judicial efficacy and the rule of law in modern societies: partisanship. In Chapter 7, we introduce what we term the Partisan Prioritization account: a rival explanation to our theory that suggests that citizens are affected more by whether a policy is championed by a copartisan than about whether or not a court says that the policy is compliant with the law. We test these rival perspectives in Germany and the United States, revealing through the use of a survey experiment that leverages the countries’ federal structures that citizens of both countries are remarkably steadfast in their willingness to punish executives – including copartisan executives – for breaching constitutional limits and flouting court orders.

Then, in Chapter 8, we expand our consideration of the threat of partisanship in two ways. First, we take into account variation in levels of judicial independence, with our account again producing an expectation that judicial efficacy depends on strong judicial independence. Second, we shift the locus of partisanship from the executive to the litigant challenging a policy. Leveraging the presence of abstract review in three of our four cases, we demonstrate that judicial independence continues to be a powerful influence on judicial efficacy, even with the appearance of a discernible – but narrow – influence from partisanship.

The key takeaway from Chapters 7 and 8 is that judicial review holds the promise – at least where courts have high levels of judicial independence – to constrain executives even in contexts where partisanship is heightened. Contrary to fears that partisanship has become an overwhelmingly pernicious threat to the rule of law, our findings suggest that independent courts are remarkably resilient in their ability to cut through the binds of partisanship as they help citizens monitor executives and coordinate their actions to reign in incumbents’ excesses.

Finally, in Chapter 9, we conclude. We discuss the implications of our findings for the broad set of research areas we engage throughout the book, ranging from theories of judicial independence to executive unilateral action to the relationship between the rule of law and democratic entrenchment. Where possible, we highlight what we see as strengths and weaknesses of our findings and research design, with a focus on opportunities for other scholars to advance the research we lay out here. We suggest that there is much left to study regarding when and how courts affect the public in the name of constraining the state. This book, we hope, is far from the last word on this important topic.