EU LAW 1.2 - PRELIMINARY RULING PROCEDURE

​The procedures of the preliminary ruling begins with the national courts or tribunals based on their own discretion request for a ruling. 

It is an obligation for the national courts of the last resorts to refer the case and request for the ruling with the few exceptions

The first exception is based on the fact that the point of law has been decided based on the previous case by the European Court of Justice as in the case of de Costa or due to its irrelevancy or the answers are obvious / acted Clair as in CILFIT

The ruling from the European Court of Justice should be applied in all cases by the national courts of the member states.