Yet, considering their different legal status and consequences, the extension from regulations to directives is not self-evident. Regulations are binding in all their parts and are directly applicable in each Member State. This implies that the Member States may not transpose the content of regulations in national legislation, or take implementing measures which might change, modify or extend their scope. Once the European Community has adopted a regulation on an issue within its competence, the Member States lose legislative authority over the matter, unless differently provided in the regulation. However, it is questionable whether this reasoning holds equally true in the case of directives.
Directives have a less immediate character.
This is the argument which was brought forth by the Council of the European Union in defence of its position. However, the argument appears to have made little impression on the Court of Justice. In light of this statement, the later argument that the Council did not deem it necessary to harmonise the measures applicable to ground water not destined for human consumption, appears doubtful at best. Furthermore, the general principle that directives are binding as to their objectives but leave the development of implementing measures up to the Member States has modified considerably throughout the years. As soon as 1977, the Court confirmed that a harmonisation directive could lawfully compel the Member States to adopt uniform rules if such action was necessary to reach the directive's objective.