Proportionality in EU law : a balancing act ?

Proportionality is a legal principle that plays a key role in constitutional review of public acts. In the EU it legitimizes the constitutional claims of EU law in the context of a multi-level legal system. The application of proportionality in the EU differs based on whether EU legal acts or legal acts of the Member States are concerned. In the former case a manifestly disproportionate test is applied, in the latter case a least restrictive means test. The stringency of the test depends in large part on the degree to which the relevant powers have been centralised. This can be considered to reflect the integration variable. There are almost no instances where strict balancing of (weighted) principles occurs. So far this is consistent with a narrative of constitutionalisation and its limits in the EU. It remains an open question how the application of the principle will develop in future, for example whether it will become more focused on balancing in cases involving individual rights.