The general principles of European Union law are general principles of law which are applied by the European Court of Justice and the national courts of the member states when determining the lawfulness of legislative and administrative measures within the European Union. General principles of European Union law may be derived from common legal principles in the various EU member states, or general principles found in international law or European Union law. General principles of law should be distinguished from rules of law as principles are more general and open-ended in the sense that they need to be honed to be applied to specific cases with correct results.