Balancing legality and legal certainty. The plea of illegality in Belgian public law and the role of the Council of State and other judicial bodies

Abstract

The Belgian legal system offers citizens a twofold protection against unlawful government action. Firstly, administrative acts can be directly challenged before the Council of State, which holds the power to suspend and annul unlawful administrative acts. Second, when faced with an illegality, any judicial body may disapply both decisions and regulations of administrative authorities. The latter is called the plea of illegality and is based on Article 159 of the Belgian Constitution.

The chapter seeks to provide an overview of the plea of illegality in the Belgian legal order. More specifically, it will examine which acts are subject to the legality review, the judicial bodies before which a plea of illegality may be raised, the extent of the legality review, the consequences of a successfully raised plea of illegality and whether there are any limitations in time for the application of this mechanism. Furthermore, it will delve into the possibility of raising the plea of illegality ex officio and discuss its relationship with the annulment procedure before the Council of State and the theory of withdrawal. Lastly, some insights on the delicate balance between the principle of legality and the principle of legal certainty will be given.

This chapter shows that, although the plea of illegality is generally given a very broad scope, an evolution toward a more restrictive interpretation of Article 159 of the Constitution – in favour of the principle of legal certainty – can be discerned in the case law. Whether this trend continues, is to be seen.