When a court or tribunal of a Member State has to apply European law in a case brought before it, it may, under Article 267 TFEU, refer a question on interpretation or validity to the Court of Justice of the European Union for a preliminary ruling, which has the effect of suspending the proceedings at the national level.  The answer to the question must be necessary to rule on the pending dispute. The possibility of making a reference for a preliminary ruling is also subject to the determination of whether a body making a reference is a “court or tribunal” which depends on a number of factors, such as whether it is established by law, whether it is permanent, whether is jurisdiction is compulsory, whether its procedure is inter partes, whether it applies rules of law and whether it is independent with respect to the executive branch.