Constitutional review of member state action: The virtues and vices of an incomplete jurisdiction

In providing preliminary rulings on the interpretation of EU law, the European Court of Justice carries out essentially review of constitutionality of Member State action. The ECJ enjoys discretion in determining the specificity of its ruling. It may give an answer so specific that it leaves the referring court no margin for maneuver and provides it with a ready-made solution to the dispute (outcome cases); it may, alternatively, provide the referring court with guidelines as to how to resolve the dispute (guidance cases); finally, it may answer the question in such general terms that, in effect, it defers to the national judiciary (deference cases). The degree of specificity is not a random exercise but a conscious judicial choice. The ECJ's discretion in this respect operates as a constitutional valve and illustrates the direct use of judicial power. This article seeks to examine the varying degrees of specificity, the types of case where each is used, the reasons which determine variations, and whether any conclusions can be drawn as to the optimum approach that the Court should take.