Federal Belgium is particularly vulnerable to the phenomenon of the joint-decision trap, where decision-making requires unanimity among executive bodies. The Belgian institutional configuration therefore creates an increased risk of abstention in the Council of the European Union, due to difficulties in domestic coordination in certain policy areas. Through a historical and legal analysis, this article traces the origins of these deadlocks : it identifies the key moments when the conditions for the trap were put in place. It then builds up a critical comparison with the mechanisms of German cooperative federalism to explore possible reforms to the Belgian system : ranging from strengthening the role of parliaments, to redefining the exclusivity of competences, or institutionalizing interministerial conferences. The Belgian case thus offers broader reflections on the capacity of federal systems to meet the demands of European integration.