The opinion was rendered by the standing commission of the Council of State. The opinions of the Council of State are not binding. Under Article 95 of the Spanish Constitution, the Constitution must be revised before any treaty is concluded that contains provisions contrary thereto.
The Council of State was of the opinion that the Constitution did not constitute an obstacle to ratification of the Rome Statute, but that the Cortes Generales (Congress) had to authorize ratification by adopting an organic law. An organic law authorizing the ratification of the Rome Statute was adopted on 4 October 2000 (Ley orgánica 6/2000 del 4 de octubre, por la que se autoriza la ratificación por España del Estatuto de la Corte Penal Internacional). Spain ratified the Statute on 24 October 2000.
The Council considered that the powers of the Prosecutor as defined in Articles 99 (4), 54(2) 93 and 96 of the Rome Statute were of the competence of national judicial authorities. The transfer of those powers to an international organization or institution is permitted under Article 93 of the Constitution.