Fights over European Union competences are dominated by ambiguity and self-interest


In 2004 Joseph Jupille published a book explaining why European Union (EU) institutions contest procedural rules governing how legislation is made. He identified jurisdictional ambiguity – the degree to which the contested bill falls under several procedural rules – and procedural incentives – what institutions stand to gain from conflict – as the main causes of what he termed procedural politics. In procedural politics, actors clash not over the substance of policy (at least not directly), but rather over which procedure should apply. The EU is known even outside academic circles to maintain a myriad of seemingly arcane legislative procedures.

In my article, I revisit the key theoretical claims made by Jupille in his seminal book. What I am chiefly interested in is to find out whether his ideas still hold water in the 21st century, or whether political scientists should discard them as out of date. To achieve this goal, I put together a new dataset of court cases in which EU institutions fight over what the legislative procedure should be in a given file. For example, the European Parliament has recently challenged the Council of the EU for choosing the seat of a new European agency without involving it in the decision. We expect such conflicts to arise when there is ambiguity about the applicable procedural rule and when the challenging EU institution has something to gain from changing the procedure. In this case, the main incentive is that of the Parliament to have a say on where EU agencies should reside, while the Council wants to continue making these decisions alone.

If we pored over each individual case, we would see that in some cases EU institutions do not clash over legislative procedures despite the theoretical conditions being fulfilled. This is not surprising. Few theories of social behaviour are only ever true or false. What I want to find out is whether the theorised conditions – the presence of ambiguity and incentives – help us explain the pattern of competence conflicts in aggregate. As a result, I look at the problem through statistical lens: what is the probability of legislation being challenged given its attributes? Does ambiguity and/or procedural incentives increase this probability and if so, by how much?

Statistical methods typically require quantified input. I measure procedural incentives by ranking all EU legislative procedures according to how much power they confer on the European Commission and the European Parliament, respectively. I then take the difference between the proposed and actually used procedure to quantify institutional incentives to challenge legislation. Measuring ambiguity is more complicated, but in a nutshell it involves comparing legislative texts against competence provisions (so called legal bases in EU jargon) to determine the extent to which there is overlap and therefore ambiguity regarding the applicable rule.

I feed my measures of ambiguity and incentives, along with other relevant information, into a statistical model designed to predict the probability of legislation being challenged before the European Court of Justice by one of the EU institutions or Member States. The main results are visualised in Figure 1. The less satisfied the Parliament and the Commission are with a procedural change – the higher the incentive – the more likely the legislation ends up before the Court of Justice. The higher the jurisdictional ambiguity of the legislation, the more likely it is procedurally disputed. We can see that when the Commission and the Parliament are very dissatisfied, and thus face strong incentives to enter into a dispute, the law is very likely to be challenged. On the contrary, the probability of a dispute is nearly zero at the opposite end of the scale. These results support the theory of procedural politics.

Figure 1: Effects of procedural incentives and jurisdictional ambiguity on the probability of a procedural dispute.


In addition to the main findings, I explored how the incidence of procedural disputes varies over time. Of particular interest is the question whether disputes are more likely to occur in the wake of changes to the EU’s constitutional framework. As competence and procedural rules change, it is more likely they will produce new sources of ambiguity. It turns out that the periods following Treaty amendments have been, with the exception of the Amsterdam Treaty, associated with more procedural disputes. With no new Treaty revision on the horizon, we should anticipate disputes to remain relatively sporadic in the years to come.

Frequently, theories in political science are formulated and tested once at their outset. As time passes, doubt about the ongoing validity of the model grows. For numerous reasons, theories are liable to become obsolete over time and there are no guarantees against loss of relevance or explanatory power. Subjecting existing theories to tests against new data is the only scientifically acceptable way of maintaining and renewing confidence in our stock of knowledge about the social world. Arguably, there are many theoretical candidates in the political science canon whose re-testing is overdue. It was with this goal in mind that I revisited Jupille’s theory of procedural politics with new data. After appraising the key tenets of the theory, I conclude that it continues to provide both a valid explanation for a part of EU politics and a falsifiable prediction about the prevalence – or, rather, absence – of procedural contestation at the current stage of European integration.

This blog post draws on the JCMS article “Procedural Politics Revisited: Institutional Incentives and Jurisdictional Ambiguity in EU Competence Disputes



Michal Ovádek is a political advisor in the European Parliament and an affiliated researcher at the Centre for Empirical Jurisprudence at KU Leuven. His research focuses on the interplay between law and politics in the European Union and Central and Eastern Europe. Twitter handle: @michal_ovadek (