Contemporary issues such as the COVID-19 pandemic and Big Tech offer opportunities to recapitulate and extend the book’s insights in this concluding chapter. More specifically, debates over public health and digital technology reveal the practical implications attending more theoretic inquiries about private actors’ status in constitutional politics. The weightiness of these issues thus supports increased urgency to study the position of private actors vis-à-vis the constitution and brings to the fore the particular value of the book’s republican framework in this enterprise. The republican framework may offer guidance regarding the contexts and goals to which horizontal application is suited, as well as the ways in which it may be further supported as a practical and a normative matter. By appreciating the ways in which horizontal application is republican, constitution-makers and courts might shore up this practice by taking steps to make it even more republican. This may come through renewed emphasis on the legislative function or contestation more generally in constitutional politics.

The US Constitution committed to equality in the Thirteenth, Fourteenth, and Fifteenth Amendments following the Civil War. Legislators and judges quickly confronted the question of what these new provisions might mean for private actors. The Radical Republicans aimed to bring the commitment to equal protection into private spaces, propagating republican discourses about the practical requirements of equal citizenship and the potential duties of private actors. However, the Supreme Court soon reached its own countervailing conclusion that only state actors, not private actors, gained duties from the Reconstruction Amendments. While this latter understanding remained firm, private actors effectively gained obligations to equality under the Civil Rights Act of 1964 and later court decisions working around the initial cabining of constitutional equality. Later debates evince a revival of republican-inflected language and arguments for something like horizontal application, even while the country’s jurists viewed such an extension of rights as basically impossible. Several other episodes in constitutional politics, both at the national and state levels, would continue to revisit this question across a range of issue areas.

The rise of the European Union elicits both theoretical and practical questions about notions of citizenship, and citizens’ duties, that transcend nation-state boundaries. Indeed, its supranational nature invites reevaluation of the concepts of citizenship and political community more generally. In a similar vein, this chapter considers the European Court of Justice’s (ECJ) practice of horizontal application in light of republican theory. The fact that the ECJ has introduced horizontal application in EU law at all is itself a point of interest, given the debatable status of the Union as a political community in the republican sense. This book’s republican framework points toward a conceptual relationship between the development of horizontal application and the fate of the European Union as, in fact, something more than a loose union of nation-states. Put differently, a full flowering of horizontal application is theoretically tied to wider acceptance of the European Union as a fully fledged political community, complete with citizens’ duties to one another and a common good of which to speak.

Citing contemporary issues, this introduction situates horizontal application as one potential response to political-legal questions involving private actors. It makes the case for renewed scholarly attention to horizontal application as an increasingly common practice in constitutional politics. More specifically, examining horizontal application through the lens of republican political theory uncovers new significance in the discourses surrounding this constitutional practice. This theoretical perspective also elucidates how horizontal application is different from traditional constitutional understandings. After introducing the book’s republican framework, Chapter 1 explains the rationale underlying the choice of contexts examined in subsequent chapters. It concludes with an explanation of the stakes, as well as the potential benefits and drawbacks of horizontal application considered in the following chapters. Finally, it previews the concluding chapter’s argument that horizontal application may be further supported with certain political and institutional adjustments to make this practice even more republican.

The framers of the Indian Constitution laid explicit foundation for horizontal application, specifically in Articles 15, 17, 23, and 24. The constitutional debates reveal deep disagreements about the country’s future. At the same time, the textual provisions for horizontal application evince a clear vision on the part of key framers, such as B. R. Ambedkar and Jawaharlal Nehru, to combat entrenched systems of caste and discrimination. These and other framers aimed to instill a new fraternity across the polity, in part by holding private actors accountable for constitutional commitments. In the ensuing years, the Supreme Court vacillated between emphasizing the constitution’s conservative and transformative elements, often under the watchful eye of other governing institutions. For example, the Court largely yielded to Indira Gandhi’s excesses during the Emergency Era of the 1970s, and later to the Hindu-nationalist BJP’s agenda. Likewise, the Court’s development of horizontal application has been somewhat uneven, applying constitutional duties to private actors in a handful of cases. In those instances, involving such salient issues as labor, sexual assault, housing, and education, the constitutional discourses that emerge echo republican rationales from the founding era.

A core purpose of South Africa’s Constitution was to modify private orderings growing out of Apartheid’s legacy of racism. Hence, the South African framers, and specifically those representing the African National Congress (ANC), had strong reason to adopt some version of horizontal application. While republican elements occur in some of the ANC’s early thought on private actors’ duties, such discourses featured less when the party had to find consensus with representatives of the Nationalist Party while negotiating the Interim Constitution. A strong formalist streak in the legal culture, concerns about preserving property rights, and the incentives of institutions such as the Supreme Court of Appeal all cut against the practice of horizontal application. Ultimately, the constitutional framers provided for both direct and indirect horizontal application in the Final Constitution. The ANC’s vision was thus fixed in this feature, and subsequent cases further cemented a break from prior orderings. Republican discourses ensued in cases involving horizontal application and perhaps most clearly in issues striking at the heart of the old Apartheid regime, such as housing and education.

Soon after the adoption of the new constitution and its own establishment, the German Constitutional Court ruled that the Basic Law had a “radiating effect” on all of German law and life, including private law. The Court reached this decision in the Lüth case amid much debate and a range of alternative understandings. Many legal actors worried that such a move toward horizontal application would blur the line between public and private law to the detriment of the civil law system. Following Lüth, jurists at all levels eventually assumed the Constitutional Court’s rationale that one could not speak of private law divorced from constitutional law. Still, certain elements of the German legal-political culture emphasized autonomy in private spaces. Likewise, constitutional actors largely considered cases relating to equality and antidiscrimination as a limit to horizontal application. As cases relating to such matters have arisen, the Constitutional Court and other constitutional actors have reexamined the reach of horizontal application. Republican discourses only extended so far in early understandings, but new forces, particularly in initiatives of the European Union, have led the Court and Bundestag to reassess how far into private spaces these rights commitments reach.

While the traditional vertical understanding of rights remains rooted in an older liberalism, the horizontal model possesses affinities with republican thought. This chapter makes these connections between constitutional practice and some of the core texts in the history of political thought. In addition to different understandings of the relationship between spheres, or the individual and community, liberal and republican thought generally conceive of liberty differently, a distinction that also maps onto the vertical and horizontal models in important ways. Rights in a horizontal understanding take on a new significance as more than mere rights, but ends as well, that potentially implicate the polity as a whole. Thus, horizontal application gives rise to new calls for parity between public and private spaces, which, in turn, amounts to a new source for understanding the duties of private actors. Such concepts as the common good and duty, integral to republican thought, come to the fore and offer a baseline for conceptualizing the parity and duties to which horizontal application gives rise. The chapter illustrates how these republican concepts occur in the context of actual cases and larger constitutional discourses, drawing examples from Germany, India, and South Africa.

In this concluding chapter, we identify two potent contributions of the concept of constitutional identity, underscoring and exploring its relationship with the associated ideas of disharmony and difference. We first discuss the relationship between constitutional identity and constitutional development, before turning to lessons that the concept of constitutional identity offers both scholars and practitioners. Against this background, we then identify three promising areas for future scholarly reflection and briefly sketch the first steps of a research agenda oriented towards carrying forward the project limned in this volume. Inspired by the analytic purpose underlying the concept of constitutional identity, our comments in this section are intended to be less prescriptive than interpretive. The scholarly futures we discuss emerge as much from the political world in which constitutional governance must now proceed as from the progress that scholars have made towards understanding the aspirations of that enterprise.