Constitutional conventions are traditionally understood as socially binding, usually unwritten, rules of constitutional importance based on precedent which cannot be enforced before courts. This traditional approach has several limitations, because it debates the normative quality of conventions rather than how to find them and where the real power lies. By doing so it is disconnected from scholarship on informal institutions in social sciences. Moreover, scholarship on constitutional conventions focuses predominantly on common law countries and conventions concerning political branches. This article pushes the boundaries in both directions. It shows how constitutional conventions can be conceptualized in civil law jurisdictions, and also identifies informal practices and constitutional conventions governing the judiciaries. On a broader level, it argues that constitutional conventions as a normative concept can help to filter the informal practices and differentiate between simple repetitive behavior on the one hand and conventions as a subset of informal institutions on the other.

While informal institutions significantly affect the functioning of courts, they also change the powers, position, and influence of individual actors in judicial systems. This Article analyzes how the presence of informal judicial institutions and practices reshapes the influence and importance of roles individual actors play in the functioning of the judiciary. The aim of this Article is three-fold. First, it maps the actors of informal judicial institutions and practices. Second, it stresses the importance of looking at actors who are not formally involved in particular judicial processes and recognized as decision-makers but have the ability to influence the judiciary informally. Third, it shows why it is necessary to keep in mind that also collective bodies can take part in informal judicial institutions and practices.

This Article describes and analyzes the role that various supranational actors from the European level play in the rise of formalization in the European states of the legal framework surrounding their judiciary. It starts from the observation that those supranational actors act as a driving force towards increased formalization via a variety of recommendations, reports, or decisions. It first provides several concrete examples of where the supranational actors act as such a driving force towards more formalization. In a second step, the Article looks more generally at how the various supranational actors think about informality surrounding the judiciary and tries to discern the rationales that underlie their position. In a third step, it assesses the various advantages and disadvantages of the rise in formalization that is propagated by the supranational actors. In doing so, the Article shows how the topic of informal judicial rules and practices cannot be understood fully without having due regard to the supranational level and contributes to the literature on the relationship between formal and informal institutions.

Most scholarly writings focus on the harmful effects of informal institutions. This article explores the positive influence of informal judicial institutions on the fundamental values of judicial systems. It develops a framework for assessing such institutions. The paper argues that the normative evaluation of informal judicial institutions is highly context-specific. Depending on their historical trajectories, different jurisdictions may emphasize different interests. Because of this, when evaluating informal judicial institutions, balancing the same values may yield different results in different jurisdictions. The recent trend towards formalization, supported by supranational institutions, goes hand-in-hand with the spreading narrative of good governance, emphasizing principles such as transparency or inclusion, principles that generally stand in tension with informality. This article cautions against emerging supranational templates insensitive to local practice.

De-democratization may take the form of executive-led attacks as well as incremental decrepitude, gradual emptying of underlying constitutional values, and state inertia. Contrary to general wisdom, both exogenous erosion and endogenous decay are heavily affected by informality. As courts are often the first institutions affected by de-democratization, this Article analyzes informality in erosion and decay of judicial institutions. It argues that such institutions interact with democracy in two core directions. The first one is endogenous and describes the decay of democratic judiciaries as a result of a long-term incongruence between formal and informal judicial institutions. The second direction captures the gradual erosion of informal institutions that have positive effects on judicial democratic resilience. These two processes, decay and erosion of informal judicial institutions, should not be overlooked. While they are less visible, slower, and often unintentional, they are as dangerous as frontal executive-led attacks on courts, because they significantly increase the window of opportunity for politicians who wish to downgrade the substance of democracy or even implement a regime change.