An important principle of the treaties, stating that EU law-making should be as light as possible and not go beyond what is strictly necessary to achieve the objectives of the treaties. Also applies to EU supra-national lawmaking.
Future
Attached to the EU Constitution is a proposal for a protocol on subsidiarity and proportionality. This would allow 1/3 of national parliaments to react, within six weeks, against a proposal for an EU-law. The Commission would then be forced to review its proposal, but not to change it.