GÄFGEN v. GERMANY JUDGMENT – SEPARATE OPINIONS 59 with the utmost caution and in cases of absolute necessity. Secondly, we wonder whether the Court, in making the assumption that more severe criminal penalties have a deterrent effect, is not at risk of creating or maintaining an illusion. The (general or individual) preventive effect of sentences has long been the subject of extensive studies and research, particularly of an empirical nature. Such studies have concluded that this effect is relative, if not limited1. Lastly, even – and no doubt especially – where criminal punishment serves the purpose of protecting rights and freedoms, at the risk of obscuring the fact that it is also a threat to rights and freedoms, we should not lose sight of the subsidiarity principle, which is a basic axiom of criminal law: use of the weapon of punishment is acceptable only if there are no other means of protecting the values or interests at stake. 6. As the Court never tires of repeating, the rights protected by the Convention cannot be theoretical and illusory but must be practical and effective. However, in the present case was the police officers’ criminal trial, which clearly had to take place, the only possible means of preventing further violations of Article 3, a provision that forms part of the core rights protected by the Convention? We do not think so. 7. According to the Court’s case-law as reiterated in the judgment, the appropriateness and sufficiency of redress for a Convention violation must be assessed with due regard to all the circumstances of the case (see paragraph 116 of the judgment). In the present case we consider that the most appropriate form of redress for the violation of Article 3 that was found and acknowledged would have been the exclusion from the trial of the evidence obtained in breach of the Convention; as this did not happen, our conclusion is that the applicant may still claim to be a “victim” within the meaning of Article 34 of the Convention. 8. It is, however, interesting to observe that, at the end of its analysis, the Court does not in principle rule out the possibility of excluding evidence as an additional measure: “... in cases in which the deployment of a method of investigation prohibited by Article 3 led to disadvantages for an applicant in criminal proceedings against him, appropriate and sufficient redress for that breach may have to entail, in addition to the above-mentioned requirements, measures of restitution addressing the issue of the continuing impact of that prohibited method of investigation on the trial, in particular the exclusion of evidence obtained by breaching Article 3.” (see paragraph 128 in fine) 1. G. Kellens, Punir. Pénologie et Droit des Sanctions Pénales, (Liège: Editions juridiques de l’Université de Liège), 2000, pp. 59 et seq.; P. Poncela, Droit de la Peine, (Paris: PUF), coll. Thémis, 2nd edition, 2001, pp. 458 et seq.