Proportionality regulates how the European Union exercises its powers. It works in much the same way as the principle of subsidiarity. The proportionality principle means that, to achieve its aims, the EU will only take the action it needs to and no more. The principle is enshrined in the Treaty on European Union under Article 5, which states: ‘the content and form of Union action shall not exceed what is necessary to achieve the objectives of the Treaties’.
This approach to responsibility and decision-making is applied as part of cohesion policy. For example, eligibility rules are decided mostly at national rather than EU level.