Rule of law and constitutionalism


The unit undertakes research in the area of Public Law broadly construed. Coming from disciplines that are mutually complementary, the researchers of the group focus their research on important questions concerning the public life of constitutional states in the globalized world. Guided by the ideas of the Rule of Law and Constitutionalism they aspire to generating a coherent body of scholarship that aims to refresh current debates in European constitutional law and theory.


The group undertakes normative, doctrinal and empirical research in the field of constitutionalism. Constitutionalism is based on the idea that the authority of government derives from and is limited by a body of fundamental principles about the moral status of citizens as free and equal persons, translated into institutional principles such as the separation of powers and the rule of law.

Currently, both within academe and public sphere, there is little effort to address the seminal questions of public life through appeal to familiar ideas and arguments which are acceptable to everyone, in some specified sense. Part of the reason for the failure is that standard legal research limits itself to one methodology, disregarding the methodological insights of the other social sciences. In contrast, our approach takes on board wider concerns, empirical and normative, about how to live a good life as citizens of a constitutional polis and how to legitimize and organize public institutions and looks for answers that are grounded on ideas and principles which are well founded in the tradition of legal and political thought. This approach is realised both by members of the group who undertake doctrinal research in the area of public law, and those who adopt a more explicit interdisciplinary approach to questions of rule of law and constitutionalism.

A significant portion of the research generated within the group is interdisciplinary. A lot of what is currently described as interdisciplinary work confines itself to a compilation of inputs from different disciplines which, notwithstanding its informative value, lacks in focus and coherence. In contrast, the members of our group view interdisciplinarity as a methodological principle that aims to deepen the impact of legal research not replace it with some other discipline. Along these lines, special care is taken to formulate our research questions from within the legal discipline, in a manner that defers expertise to a host of kin disciplines for any concepts that fall within their special expertise. The output of this inquiry generates research that is highly relevant to legal scholarship, while it is strengthened by the expert knowledge of other disciplines, which otherwise would have remained opaque to the legal scholar. This conception of interdisciplinarity is well-suited for pushing the boundaries of legal research while generating important insights that are of practical value to legal academics and practitioners alike.

Research Questions

The research interests of the group comprise four distinct themes: foundational normative issues; substantive principles; questions of institutional design; genealogy of institutions.

Foundational issues

Under foundational issues the research of the group considers the question ‘are there right answers in constitutional law?’ Making extensive use of interdisciplinary research in law, political and moral philosophy, we attempt to demonstrate that the content of constitutional law is to be kept distinct from legal texts, the acts of legal officials or other components of the legal practice, when those are viewed in isolation. In contrast, we defend the thesis that those distinct components need to be evaluated in their mutual interaction and in the light of the substantive principles of constitutional law, which underpin our constitutional practices. Such principles are, in turn, formulated in the light of more fundamental evaluations about the point of structuring political communities as self-governed collectives that respect the freedom and equality of their members. The outcome is a set of mutually supportive arguments (that is, a theory), which can ground better interpretations of the constitution and distinguish them from others that are less plausible.

These theoretical assumptions suggest a cluster of research hypotheses, which inform the research of the team:

  • How do constitutionalism and the rule of law determine the relation between legislative intention and the content of the constitution?
  • What are the substantive reasons for the requirement that the law be justifiable to everyone rather than consist in ad hoc rulings of particular actors?
  • In what sense is the question ‘who counts as a member of a political community?’ one of substantive theory, not of authoritative decision or practice?
  • Should the justification of democratic will-formation be sensitive to the right to freedom and equal treatment of everyone who ought (as a matter of justice) to count as member of the political community?

Substantive principles

While constitutionalism and the rule of law are often taken to capture formal aspects of constitutional law, we are drawn to a more complex picture. In the light of our foundational assumptions we demonstrate that those bring to expression complex relations between other substantive principles of political morality, such as individual freedom, equality, fairness and democracy. Under this picture constitutionalism and the rule of law perform their formal functions (limiting government; generating legal certainty; supporting the separation of powers), in the light of their substantive normative content (individual freedom; equality and fairness; democracy). Along these lines several of the traditional dualisms in constitutional theory and practice acquire a different dynamic: resolving conflicts between individual rights and equality/justice may no longer be thought of as some pragmatic compromise, but as the result of substantive argument within the purview of the principle of proportionality (which, in turn, is grounded on the ideas of constitutionalism and the rule of law). Another prominent example is the alleged contrast between democracy and individual rights: democracy is not in tension with rights if it itself requires the protection of those very rights to justice and freedom which it sometimes is said to threaten. Such an understanding of democracy requires that citizens have more than just an equal vote; it means that they participate as equal partners, having an equal voice and an equal stake in the result. Rather than shunning such conflicts our understanding of constitutional law, attempts to provide a comprehensive theory that aims to integrate the various normative elements (values, principles) into a coherent whole.

Such foundational questions acquire major practical relevance when we move to examine the role of the various actors under a constitutional polity. In this respect, the guiding research questions are:

  • What is the role of the various actors in a political community in ‘shaping’ the meaning or content of constitutional principles?
  • What is the content of principles such as (deliberative) democracy, the separation of powers, the rule of law and which is the contribution of constitutional courts to the explication thereof?
  • What is the role and functioning of parliaments within constitutional polities; their interaction with other actors inside and across levels of governance (in this context we deal with the principle of subsidiarity); an account of parliaments’ contribution to representative law-making?
  • Which theory can generate a coherent account of constitutional practice, in the light of the substantive principles that ought to inform it?

Questions of institutional design

Bringing together foundational questions with substantive principle the members of the research team are ideally placed for making concrete policy recommendations and offering solutions concerning the appropriate design of constitutional institutions. In contrast to many other similar efforts, our team strives for solutions which, in considering the ‘bigger picture’ of constitutional law, remain relevant in a principled manner, rather than forming ad hoc responses that fail to resist the test of time.

A particular interest of the group revolves around the question ‘how to best shape constitutional review in specific contexts of governance?’ In the absence of ready-made answers, the principles informing the political life of a community need to be implemented in multiple contexts (democratic, multicultural or consensus societies), and across different levels of jurisdiction (national, multi-layered, international).

Changing contexts create often the impression that constitutional review is caught between irresolvable dilemmas, which make it hostage to the empirical circumstances of each situation. Contrary to that appearance we aim to show that the substantive constraints that are entailed by the core ideas of constitutionalism and the rule of law make it the case that it is possible to arrive at principled solutions across a varied number of contexts. To illustrate this point, our researchers endeavor to test their theories of constitutionalism and the rule of law against concrete legal and socio-political settings.

Among the questions currently driving this aspect of the group’s research count:

  • Within the context of consensus democracy how can a constitutional court reconcile its role to be a forum of deliberation with that of the guarantor of consensus?
  • Whether and how the theory of deliberative democracy can explain fundamental tensions between constitutionalism, including constitutional review, and democracy?
  • Do courts further democracy by protecting and expanding human and socio-economic rights?
  • What, in terms of legal and socio-political factors, explains the success or failure of constitutional courts as deliberative agents?

Genealogy of Institutions

Finally the research approach is sensitive to the contextual parameters of the constitutional doctrine. Combining their expertise in constitutional law with a strong interest in legal and constitutional history, political science and the sociology of political institutions, the members of the research team strive for legal scholarship that is firmly embedded into the history of political institutions and their understanding not only in their mutual normative relations but also as outcomes of human practices, which are causally determined by the interests, needs and motives of the particular individual and collective agents who are involved in them.

The constitution and constitutional law more than other branches of law are exposed to political power relationships. The interpretations of the articles of the written constitution often evolve under the influence of the political context, albeit not in an unprincipled manner. Moreover, constitutional law also consists of unwritten law, such as custom, precedents and conventions, which have developed throughout the political history of the community. Finally, non-institutional actors, such as political parties, play a significant role in the “life of the constitution”.

These considerations lead to the following cluster of questions:

  • In what ways can our understanding of the meaning of ‘constitutionalism’ be enhanced by an inquiry into the significance of the written constitution, the relationship between written and unwritten constitutional law, and between the “law of the constitution” and “the conventions of the constitution?
  • How can historical analyses of aspects of the constitutional system (in the Belgian system e.g. the monarchy, federalism, language legislation; in the European Union e.g. the relations between the EU institutions) contribute to explanations of the interplay between the constitution and political power?
  • What is the position and role of the political actors in the “life of the constitution” or a constitutional treaty?