La prueba ilícita: la razón de ser y el derecho de la Unión Europea

REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 La prueba ilícita: la razón de ser y el derecho de la Unión Europea* Exclusionary rules of evidence: rationale and European Union Law RICCARDO BIANCHI Fiscalía de Milán. Investigador visitante en la Universidad de Valladolid [email protected] ORCID: 0009-0004-8638-323X Recibido: 14/10/2024. Aceptado: 14/12/2024 Cómo citar: Bianchi, Riccardo, “La prueba ilícita: la razón de ser y el derecho de la Unión Europea”, Revista de Estudios Europeos, 85 (2025): 430-463. Artículo de acceso abierto distribuida bajo una Licencia Creative Commons Atribución 4.0 Internacional (CC-BY 4.0) DOI: https://doi.org/10.24197/ree.85.2025.430-463 Resumen: Análisis, comparación y crítica son las bases de los estudios comparativos. Este trabajo, que se centra en las reglas de exclusión de pruebas, utiliza la comparación entre los sistemas italiano y español con tres objetivos: (a) entender la razón de ser de la exclusión; (b) aplicar las conclusiones al derecho de la Unión Europea para determinar si (b.1) exige la expulsión de ciertas pruebas o (b.2) obliga al juez nacional a no aplicar la regla; (c) y evaluar si los balances realizados por el juez son una solución adecuada en el contexto europeo. Palabras clave: prueba ilícita; supremacía europea; derechos fundamentales; proporcionalidad Abstract: Analysis, comparison, and critique are the actions that constitute comparative studies. This work, which focuses on exclusionary rules of evidence, employs legal comparison between the Italian and Spanish systems for three purposes: (a) to understand the rationale behind the exclusion of evidence from proceedings; (b) to apply the conclusions drawn to European law, to determine whether the latter (b.1) requires the exclusion of certain evidence or (b.2) conversely obliges the national judge to disregard the rule; (c) finally, to use the results of the comparison to assess whether judicial balancing is an appropriate solution, even within the European context. Keywords: illegally obtained evidence; European supremacy; fundamental rights; proportionality * Este trabajo se ha realizado en el marco de un periodo de investigación en la Universidad de Valladolid, sobre la regulación de la prueba ilícita en España. El proyecto de investigación ha sido aprobado tanto por la Universidad de Milán como por la Universidad de Valladolid). La prueba ilícita: la razón de ser y el derecho de la Unión Europea 431 REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 INTRODUCTION How are rights capable of being limited? The issue is the result of extensive doctrinal elaboration, and Article 52 of the Charter of Fundamental Rights of the European Union synthesizes its conclusions in relation to Union law. Limitations require a legal provision, which must not infringe on the essential content of the right and must be necessary and aligned with objectives recognized by Union law or with the need to protect others’ rights and freedoms. This must be in accordance with the principle of proportionality. Thus, requirements for restrictions are summarized as follows: legitimacy of the aim pursued, suitability of the measure to the aim, necessity as the absence of alternatives, and strict proportionality. The latter involves balancing conflicting interests to allocate victory and defeat between them in given circumstances (in circumstance X, interest Y prevails). Having said that, the aim of this work is to employ comparative methodologies to identify the interest that exclusionary rules are intended to protect. The findings will serve to develop considerations related to European law. 1. RIGHTS VS. FACT-FINDING: THE LACK OF BALANCING. STC 114/1984 F. P. N. was peacefully talking on the phone, unaware that his interlocutor was recording the conversation. He should have been more cautious, as the recording ultimately cost him his job, due to professional shortcomings and breaches of loyalty to the company. He challenged the decision, but the judge in Alicante rejected his claims, as did the Supreme Court. F. P. N. appealed to the Constitutional Court, presenting two claims: violation of Article 18.3 of the Spanish Constitution (secrecy of communications) and infringement of Article 24 (the right to a trial “con todas las garantías”). The judges’ reasoning (STC 114/1984 1 ) followed a labyrinthine path but let us try to figure it out: Article 10.1 of the Spanish Constitution establishes fundamental rights as “inviolables”; these include the rights enumerated in Section I, Chapter II, Title I of the Constitution. Article 24.2 1 STS nº 114/1984 (29th November), nº proc. 167/1984. ECLI:ES:TC:1984:114. 432 Riccardo Bianchi REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 mandates procedures “con todas las garantías” and any violation of these procedures would offend the principle of equality (Article 14 of the Constitution) between the parties. Consequently, if an action violates these rights, it is deemed invalid. 2 Thus, where there is a violation of legality, it is necessary to determine whether this constitutes an infringement of a fundamental right. In fact, not every illegality compromises fundamental legal positions. The ruling was groundbreaking, a leading case, and the following year it was codified into law: Article 11.1 LOPJ 3 . “Evidence obtained […] by violating fundamental rights or freedoms shall have no effect”. But the law goes further: both evidence that is directly obtained by violating fundamental rights and evidence that is gathered indirectly are poisoned 4 . The Court balanced legality against the interest in establishing the facts. The goal was to discover the criterion according to which one prevails over the other when a rule is violated. The judges identified this criterion in fundamental rights. a) When does fact-finding prevail over legality? When no fundamental right is violated. Evidence is irregular but may be used. b) When does legality prevail over fact-finding? When a fundamental right is violated. Evidence is irregular and cannot be used. The weighing that was conducted was not between rights and factfinding. The statement “the violation of a fundamental right causes the non-usability of evidence” does not balance any rights; it instead sets an external limit to the establishment of the facts. It is this limit that ordinary 2 The commentator clarified an important difference: the violation of a fundamental right makes the evidence ilícita; the use of such evidence in the proceedings infringes the right to a trial con todas las garantías. See González Montes, José Luis (2006), “La prueba ilícita”, Persona y Derecho, 54, p. 368. 3 Ley Orgánica del Poder Judicial (01/07/1985 nº 6). 4 For a comprehensive summary on the subject of illegal evidence in Spain, see: Miranda Estrampes, Manuel (2003), “La regla de exclusión de la prueba ilícita: historia de su nacimiento y de su progresiva limitación”, Jueces Para la Democracia, 43, pp. 53-66; furthermore: Planchadell Gargallo, Andrea (2020), “El largo y tortuoso camino de la prueba prohibida en nuestra jurisprudencia”, in Asensio Mellado, José María and Alba Rosell Corbelle (eds.), Derecho probatorio y otros estudios procesales: Libro homenaje a Vicente Gimeno Sendra, Madrid, Ediciones Jurídicas Castillo de Luna, pp. 1645-1664. La prueba ilícita: la razón de ser y el derecho de la Unión Europea 433 REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 judges will be called upon to verify: if it is met, then the evidentiary element will be excluded from the body of knowledge. Balancing two interests means determining in which instances one prevails and when the other does. According to the Constitutional Court ruling 114/1984, there are no situations in which fundamental rights fall apart (when there is a violation of the rules): therefore, they were not balanced against anything. The solution is not dissimilar to Italy’s. Just as in Spain the violation of a fundamental right is grounds for the non-usability 5 of evidence, in Italy the violation of a “prohibition established by law” (Article 191 of the Code of Criminal Procedure) has the same effect 6 . In both cases, the system is rigid, with no room for the ordinary judge to assess which interest should prevail 7 . Unfortunately, verbal forms do not correspond to reality. Or rather, they did until jurisprudential interpretations betrayed the spirit of ruling 114/1984, despite being incorporated into law (Article 11.1 LOPJ). What differs is the complexity of legal frameworks: the Italian one stands out for its greater detail and variety. It is more detailed because it outlines specific evidentiary prohibitions; it is more varied because there are prohibitions that protect not only constitutional rights but also other interests (for instance, the reliability of the evidentiary element 8 ). For example, flagrancy and escape justify a search initiated by law enforcement. Except for these cases, there is a prohibition on conducting searches. This is provided for in Article 352 of the Italian Code of Criminal Procedure. By introducing the tool of search into the legal system and setting out its related regulations, the legislator has balanced rights and truth. Therefore, inviolability of the home will yield when it comes to searching 5 To avoid confusion, I have preferred to use the term “usability” as the translation of the Italian “utilizzabilità”, and not the more ambiguous “admissibility”. In the negative form, the terms are “non-usability” and “inutilizzabilità”. 6 See two of the earliest and most important doctrinal writings on the subject: Galantini, Novella (1992), L’inutilizzabilità della prova nel processo penale, Padova, CEDAM; Nobili, Massimo (1991), “Divieti probatori e sanzioni”, Giustizia Penale, 3, pp. 641-651. 7 Tonini, Paolo and Carlotta Conti (2014), Il diritto delle prove penali, Milano, Giuffrè, p. 104. 8 In Spain as well there are procedural rules that protect interests different from fundamental rights (for example, the prohibition of leading questions), but these are not attributable to the provisions of Article 11.1 LOPJ. 434 Riccardo Bianchi REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 for the corpus delicti after flagrancy. The limitation on taking action out of these circumstances is designed to safeguard the individual’s rights. But if we look solely at Article 352, we will be unaware of what happens to evidence gathered in breach of this regulation. In rerum natura, being illegal and unusable are not bound by any necessary connection. The prohibition protects rights, but ontologically nothing requires a prohibition to be linked to the non-usability of evidence. A legal norm is required: it is Article 191 of the Code of Criminal Procedure, when it comes to a general defect; it is the specific sanction, when it comes to a special defect (for example, Article 271 regarding wiretapping). So, did the legislator weigh rights against the establishment of the facts? No, when it imposes nonusability: here legality and truth were weighed, and this was done by using fundamental right as balancing criterion. To summarize: - Legislators establish rules (for searches, wiretaps, forced medical examinations) by balancing rights and the establishment of the fact. - STC 114/1984 and the Italian Code introduced non-usability by balancing legality and truth. At this point, a question naturally arises. Is it reasonable to always prioritize legality in the face of a fundamental right’s violation? 9 There are rules that protect fundamental rights. These disciplines impose boundaries: if violated, STC 114/1984 and the Italian Criminal Procedure Code exclude the results of the operations. Was it terribly difficult to respect them? There is nothing that prevents from verifying the fact, provided the rules are respected. Confirmation is provided by STC 114/1984, which cited foreign jurisprudence effectively and without hesitation. The lesson is Italian and was found in the judgement of the Constitutional Court 34/1973 10 . In a significant passage, the Italian Court proclaimed a “need for legality […] (particularly when it comes to observing the Constitution)”. 2. EXCEPTIONS TO EXCLUSIONARY RULES: AN OVERVIEW 9 De La Oliva Santos, Andrés (2003), “Sobre la ineficacia de las pruebas ilícitamente obtenidas”, Tribunales de Justicia, 8-9, pp. 91-108. 10 FJ 3. La prueba ilícita: la razón de ser y el derecho de la Unión Europea 435 REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 Spanish constitutional case law has reached conclusions that are far from the original proclamations: it will give relevance to good faith in the execution of the act, which seems more aligned with a deterrent logic (what matters is discouraging willful abuses by the authorities) rather than with the protection of rights. To sum up, the situations that determine the overcoming of the exclusionary rule are as follows 11 . a) the agents’ good faith in obtaining the evidence (STC 22/2003 12 ) or the private nature of the person obtaining it (STS 116/2017 and STC 97/2019 13 ); b) with regard to the fruit of the poisonous tree doctrine, the independence of evidence (if the second evidence does not depend on the invalid one, it will be considered valid), the inevitability of discovery (if the invalid act had not been carried out, the second piece of evidence would still have been obtained), the fragility of the link connecting evidence (if there is a long chain of procedural acts between the invalid evidence and the questionable one, it will be excessive to exclude the latter of the timeline), the random nature of discovery (for example, certain illegal wiretaps may reveal a crime different from the one for which they were authorized), and, generally, la conexión de antijuridicidad (which requires a balancing between fact-finding and the protection of rights, taking into account the circumstances of the specific case). Exceptions to the rule cannot be studied analytically in this contribution, except for the subjective element in obtaining evidence. 11 See Planchadell Gargallo, Andrea (2014), La prueba prohibida: evolución jurisprudencial: (comentario a las sentencias que marcan el camino), Cizur Menor (Navarra), Thomson Reuters-Aranzadi; Díaz Cabiale, José Antonio and Ricardo Martín Morales (2002), “La teoría de la conexión de antijuricidad”, Jueces Para la Democracia, 43, pp. 39-49; Lozano Eiroa, Marta (2012), “Prueba prohibida y confesión: la excepción de la «conexión de antijuridicidad»”, Revista General de Derecho Procesal, 28. Regarding the most recent exception: Carrillo del Teso, Ana (2020), “El diálogo judicial sobre las “listas Falciani”: los diferentes criterios de su admisión como prueba”, in Asensio Mellado, José María and Alba Rosell Corbelle (eds.), Derecho probatorio y otros estudios procesales: Libro homenaje a Vicente Gimeno Sendra, Madrid, Ediciones Jurídicas Castillo de Luna, pp. 419-434. To understand how Spanish case law has been inspired by U.S. law, see: Miranda Estrampes, Manuel (2019), Prueba ilícita y regla de exclusión en el sistema estadounidense: crónica de una muerte anunciada, Madrid, Marcial Pons; Alcaide González, José Manuel (2013), La prueba ilícita penal: decadencia y extinción: jurisprudencia práctica comparada con EEUU, Alhaurín el Grande (Málaga), Editorial Ley 57. 12 STC nº 22/2003 (29th February), nº proc. 4400/1999. ECLI:ES:TC:2003:22. 13 STC nº 97/2019 (16th July), nº proc. 1805/2017. ECLI:ES:TC:2019:97. 436 Riccardo Bianchi REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 Indeed, this work aims at identifying the correct interest protected by the exclusion of evidence, in order to deduce relevant consequences for European law. To achieve this goal, it is important to examine the concept of good faith, and this analysis will be carried out in the following paragraph. 3. EXCLUSIONARY RULES’ TELEOLOGY AND THE EUROPEAN COURT OF HUMAN RIGHTS Good faith is the exception that STC 22/2003 14 created to the exclusion of evidence obtained directly from the violation of a fundamental right. The court’s conclusions ignored a significant fact: maintaining the rule of exclusion for illegal evidence entails certain corollaries that must be respected - among these ones, the violation of a right requires to be objective. 15 Facing the choice between the use or exclusion of the evidentiary element, the judge responds by determining whether a fundamental right has been unduly violated, regardless of the actor’s intent or fault. The subjective element is a matter for a future criminal trial against the violator: the dialectic between prosecution and defense will yield the correct answer. Conversely, introspective analysis is of no interest in the proceeding where the violation occurred, given that evidentiary purposes are indifferent to the good or bad faith of the procedural protagonist. What matters is whether a fundamental right (or a probative prohibition - Article 191 of the Italian Code) has been violated (STC 114/1984 and Article 11.1 LOPJ). Violating a legal right has an entirely objective significance, and even assuming a lack of intent or fault, the outcome would remain unchanged: once the offense has been established, it remains. How could good faith exclude the prejudice to the right? Having established that good faith is incapable of miraculous pardons, the outcome leads us to an inquiry into the rationale behind non-usability. It is not the deterrent effect, a purpose that belongs to criminal sanctions and is thus unrelated to the exclusion of evidence. Indeed, deterrence does 14 STC nº 22/2003 (29th February), nº proc. 4400/1999. ECLI:ES:TC:2003:22. 15 Miranda Estrampes, Manuel (2010), “La prueba ilícita: la regla de exclusión probatoria y sus excepciones”, Revista Catalana de Seguretat Pública, 22, p. 140. The author highlights the contradiction between STC 22/2003 and 114/1984. La prueba ilícita: la razón de ser y el derecho de la Unión Europea 437 REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 not equate with the protection of legality, as penalizing violations of norms may have no deterrent effect whatsoever (as we have seen in cases of actions conducted without intent or fault). The non-usability is a pathology with physiological purposes: it protects a legality that safeguards rights and, in this way, ensures a fair trial 16 . Non-usability does not prevent; it repairs and protects 17 . In our Europe a need of fairness in trials prevails, enshrined by Article 6 of the European Convention: “everyone is entitled to a fair […] hearing”. Prognostic oracles about deterrent effectiveness are insignificant to achieve fairness: if fundamental rights are unduly violated, it does not matter that the exclusion of evidence cannot serve preventive purposes (even if the police acted in good faith). Assuming that undue violation and injustice are synonyms, the former will not undergo metamorphosis due to the operators’ good faith: the absence of preventive necessities is not Circe; it does not transform injustice into fairness. Constitutions address this issue within national borders: Article 111 of the Italian Constitution requires a “fair trial regulated by law”. Article 24 of the Spanish Constitution proclaims one “con todas las garantías”. Ergo, the sanction of non-usability is procedural rather than substantive; the primary object of protection is legality, and it is crucial to emphasize the value of such legality in safeguarding constitutional rights: a trial would not be fair if it considered evidence obtained in violation of norms that protect fundamental rights... regardless of what the majority of the European Court might think 18 . Indeed, much has been said about good 16 The constitutional importance is emphasized by Asensio Mellado, José María (2013), “La exclusión de la prueba ilícita en la fase de instrucción como expresión de garantía de los derechos fundamentales”, Diario la Ley, 8009, p. 2: the author consequently asserts the need for the illegality of evidence to be declared immediately. The doctrinal “dialogue” that this article has created is interesting. See: Gimeno Sendra, Vicente (2013), “La improcedencia de la exclusión de la prueba ilícita en la instrucción (contestación al artículo del Prof. Asencio)”, Diario la Ley, 8021. The latter article challenges the previous thesis, according to which the Juez de instrucción is authorized to exclude invalid evidence. Specifically, the doctrinal work argues that the evaluation of evidence (a phase distinct from its collection) falls under the jurisdiction of the deciding judge. 17 See Roca Martínez, José María, Procesos y Prueba Prohibida, Madrid, Dykinson, S.L., p. 140; Armenta Deu, Teresa (2020), “Prueba ilícita y regla de exclusión: perspectiva subjetiva”, in Asensio Mellado, José María and Alba Rosell Corbelle (eds.), Derecho probatorio y otros estudios procesales: Libro homenaje a Vicente Gimeno Sendra, Madrid, Ediciones Jurídicas Castillo de Luna, pp. 119-120. 18 Ölçer, Pinar (2013), “The European Court of Human Rights: The Fair Trial Analysis Under Article 6 of the European Convention of Human Rights”, in Stephen Thaman (ed.), 438 Riccardo Bianchi REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 faith, the deterrent effect, legality and rights; and in Strasbourg, certain resonances have inspired the dissenting opinions of Meyer, Pettiti, Spielmann, and Carrillo Salcedo (ruling Schenk v. Switzerland, 1988 19 ). They objected to the notion that Article 6 of the European Convention does not mandate the exclusion of evidence obtained in violation of the guarantees required by the Convention. The majority, however, deduced it from three observations: that the Court’s role is to review the fairness of the criminal proceedings as a whole, that the applicant had great opportunities for cross-examination, and that the improper recording was not the only piece of evidence supporting the conviction. Therefore, the adversarial principle was upheld in this case, but one must wonder how the Court made the entire justice of a trial depend on the dialectic regarding the evidence. How can a trial be fair when evidence that violates a fundamental right has been used? The Court was less delicate in Khan v. UK, 2000 20 , as it firmly declared the violation of Article 8 of the Convention: a State that intercepts communications without a legal basis breaks the Treaty. However, the fair trial required by Article 6 was deemed unaffected by the contradictions we observed in Schenk. Yet, even in this instance, we hear echoes of our discussions: Judge Loucaides dissented 21 . 4. VIOLATION OF A FUNDAMENTAL RIGHT AND BREACH OF LEGALITY In criminal proceedings, under what circumstances does a violation of a fundamental right occur? Despite expectations, the answer seems straightforward: when rules that aim at protecting constitutional rights are violated. In other words, there is a legality that guarantees rights and the breach originates from its violation. But what kind of legality? Constitutional alone? Or does it also include ordinary one? Certain Spanish legal literature has put forward a rigid alternative: one or the other kind of legality. It argued that discourse on fundamental rights Exclusionary Rules in Comparative Law, Dordrecht, Springer, pp. 371-399; with regard to more specific topics, see: Bachmaier Winter, Lorena (2013), “Transnational Criminal Proceedings, Witness Evidence and Confrontation: Lessons from the ECtHR’s Case Law”, Utrecht Law Review, 9, pp. 127-146. 19 Case Schenk v. Switzerland (18/07/1988), ap. nº 10862/1984. 20 Case Khan v. UK (12/05/2000), ap. nº 35394/1997. 21 For subsequent developments in the case law of the ECHR, see the final paragraph (n°7). La prueba ilícita: la razón de ser y el derecho de la Unión Europea 445 REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 Access to telephone traffic data reveals intimate aspects of life, such as habits, locations, and people. This leads to the prohibition: a national law that does not restrict the acquisition of such data to the investigation (and prevention as well) of serious crimes is contrary to Union law. If anaphora identifies significant repetitions, then the recurrent use of the word “serious” surely underscores the Court’s central message: in the quoted passage alone, the word “serious” appears three times. There are two reasons for this conclusion: legislative proportionality (which requires legitimate objectives and measures that are necessary and proportionate to the objective) and the protection of private life. To evaluate the seriousness of an investigative measure, what criteria should be applied? The Advocate General proposed considering the types of data examined and the duration of the measure, as long periods of time provide more data. However, the Court responded that even brief periods can offer substantial insights into a person’s life. Further, how should the seriousness of a crime be assessed? The Advocate General advised considering the severity of the penalty, the nature of the crime, the social harm, and the vulnerability of the victim. It is the judge’s task to evaluate the legitimacy of the measure. Given that the public prosecutor is an independent yet partial figure, a legal system that empowers the prosecutor to authorize access to data does not meet the impartiality and neutrality requirements stipulated by European law. The observation was apt, until the familiar judicial proportionality was interpolated: It is a requirement of such a review that the court [...] must be able to strike a fair balance between, on the one hand, the interests relating to the needs of the investigation in the context of combating crime and, on the other, the fundamental rights to privacy and protection of personal data of the persons whose data are concerned by the access. 37 As we will explain in the final paragraph (n°7), in matters of evidence exclusionary rules, the assessment of proportionality should be carried out solely by the legislator, and not by the judge: it is a matter of appropriateness. 37 Para. 52. 446 Riccardo Bianchi REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 b) Prohibition of Use. In the absence of European provisions, it is up to the States to establish prohibitions on the use of evidence, a conclusion derived by the Court from the principle of autonomy. The distinction between the two categories of prohibitions is made clear by the judges’ words: the States are to set the rules for the evaluation of evidence, even when it is obtained “by general and indiscriminate retention of such data contrary to EU law”. However, the protections of rights enshrined by the Union must not be less favorable than those provided for similar situations under national law (principle of equivalence). Additionally, the exercise of rights must not be rendered excessively burdensome (principle of effectiveness). Effectiveness is a valuable concept, as it could be a plausible tool for enforcing prohibitions on use. The Court did not fully embrace this, or did so only partially: while the right to contest evidence is preserved, Union law does not mandate the exclusion of evidence. Therefore, data obtained in violation of European law will only be inutilizzabili if the party has not been provided with opportunities to contest the evidence. This is a consequence derived from a strict interpretation of the right to a fair trial. The European Court of Human Rights’ words 38 resonate in the judgement like an echo. 5. 4. Prokuratuur: the implications for Italian Law The previous version of Article 132 of D.lgs. 196/2003 39 was deemed by Italian judges to be compatible with Article 15 of Directive 2002/58. This provision granted the competence for acquiring telephone records to a motivated order of the public prosecutor 40 ; there was no restriction to serious crimes. It has been noted that some European judgements anticipated the Prokuratuur’s proclamations, but in Italy the prevailing view bypassed them: it emphasized that the Italian prosecutor is an authority endowed with the necessary guarantees and that the assessment 38 See § 4. 39 D.lgs. 30/06/2023 nº 196. 40 Tonini, Paolo and Carlotta Conti (2021), Manuale di procedura penale, Milano, Giuffrè, pp. 432-433. La prueba ilícita: la razón de ser y el derecho de la Unión Europea 447 REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 of criminal severity can be made in concrete terms (i.e., the prosecutor can assess proportionality, creating a balancing act subject to judicial review) 41 . The CJEU’s Prokuratuur ruling has definitively refuted these arguments, demanding a swift legislative response. This intervention was implemented on September with D.L. 132/2021 42 , which amends the above-mentioned Article 132. Today, the provision is in line with the Court’s requirements, also establishing that its violation results in the nonusability of the obtained evidence. Meanwhile, uncertainties persisted regarding the fate of evidence acquired in violation of European law. Article 15 of Directive 2002/58 imposes a prohibition on the use of such evidence, as stated by the Court. In Italy, Article 191 Code of Criminal Procedure determines the consequences of violating prohibitions: the non-usability of data and its relevance at any stage of the proceedings; any corrective measures by the preliminary investigating judge are ineffective, as there is no provision for curing the defect. Case law quickly solved the issue by downgrading the decision to a measure with vague terms and no direct effects 43 . This is incorrect. If a CJEU ruling identifies an incompatibility between national and European law, there can be no indirect effect: the ruling is directed at the lower court but generates erga omnes and retroactive effects; any state authority, including judges, has the obligation to act to resolve the normative conflict 44 . 5. 5. EncroChat A drug trafficking network seemed to hover across European borders, catching the attention of multiple public prosecutors’ offices. The Frankfurt office opted for a European Investigation Order (three, two of which were actually supplementary), aiming at obtaining data captured by a trojan infiltrated in encrypted conversations via the EncroChat system 45 , 41 For instance, Cass. 4873/2019 (ud. 25/09/2019). 42 D.L. 30/09/2021 nº 132 (Article 1). The decree was converted by L. 23/11/2021 nº 178. 43 Cass. 33116/2021 (ud. 02/07/2021). 44 Adam, Roberto and Antonio Tizzano, Manuale di diritto dell’Unione Europea, Torino, Giappichelli, pp. 351-354. 45 For an introduction to the topic, refer to: Peralta Gutiérrez, Alfonso and Francisco Javier Parra Iglesias (2021), “Incorporación de prueba penal obtenida en proceso judicial 448 Riccardo Bianchi REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 with France as destination. The cooperation was successful, but the Berlin Regional Court did not overlook the lessons of Prokuratuur. A preliminary ruling was requested. From this lesson, the Berlin Court concluded that (a) it is up to the judge to issue an EIO, (b) limiting it to the investigation of serious crimes supported by facts, and (c) verifying its legitimacy in light of national law, (d) the principle of equivalence, and (f) effectiveness. The investigation must focus on serious crimes, and the order must be based on facts, as required by the principles of proportionality and necessity set out in Article 6 of Directive 2014/41. Furthermore, the principle of equivalence dictates that data collected from an interception which is not ordered by a judge and for a crime which is not justifiable under German law are inadmissible. But the core of the objections lies in the effectiveness of Union law: in Berlin, the judge connected this to the prohibition of using evidence that contravenes European law (illegitimacy of the EIO). The Advocate General of the Court of Justice responded negatively: the assessment of evidence is an issue outside the scope of the EIO Directive; since it is not covered, the Member States are responsible for regulating it. The Court agreed (CJEU EncroChat, 2024 46 ), justifying it with the historical principle of autonomy (dating back to CJEU ReweZentralfinanz, 1976 47 ): establishing procedures for the protection of rights is a free operation for the States, in the absence of European rules; the Member States must only ensure a minimum level of effectiveness and equivalence. From these premises, the usual slogan followed, stating that the exclusion of evidence is inevitable only in the absence of a dialectic on evidence, a refrain to which the reasoning found a normative link: it is Article 14, paragraph 7, of the EIO Directive, which imposes a fair trial in the assessment of evidence. 6. EUROPEAN INTEREST AND NON-USABILITY: THE CONFLICT extranjero: casos EncroChat y Sky ECC”, La Ley Penal, 149; Rubio Moreno, Felipe (2021), “Caso EncroChat y la prueba resultante de las intervenciones masivas de comunicaciones encriptadas en procesos penales extranjeros”, La Ley Penal, 153. For a critical analysis of the matter, consider: Oerlemans, Jan-Jaap and Dave van Toor, (2022), “Legal Aspects of the EncroChat Operation: A Human Rights Perspective”, European Journal of Crime, Criminal Law and Criminal Justice, 30, pp. 309-328. 46 Case EncroChat (30/04/2024), C-178/22. ECLI:EU:C:2024:372. 47 Case Rewe-Zentralfinanz (16/12/1976), C-33/76. ECLI:EU:1976:188. La prueba ilícita: la razón de ser y el derecho de la Unión Europea 449 REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 6. 1. European supremacy The previous paragraph attempted to identify a European interest protected by the procedural sanction of non-usability. It failed to do so, despite the supranational legal order’s protection of legality and rights. However, the relationship between prohibitions on the use of evidence and EU law is not limited to issues of compliance; it can also be examined in reverse: an inquiry into whether such prohibitions are contrary to the supremacy of that legal order. Autonomous and integrated within national legal systems, the European supernova succeeds in asserting its effective existence, that is so vital that it does not require a national transformation of European laws, as if they were foreign (CJEU Costa / Enel, 1964 48 ; this also applies to directives). In fact, they are not foreign; rather, they operate within the Member States without any inferiority complex, as it is impossible for national authorities to give priority to a domestic measure over European law. The consequence is the disapplication of any national rule that is not in conformity with the European standard, provided it is directly applicable (CJEU Simmenthal, 1978 49 ). This concept applies to the fight against crime that harms the Union’s financial interests, which Article 325(1) TFEU and Article 1 of the PFI Convention require to be effective 50 . Therefore, national statutes of limitations are inapplicable 51 . But what about prohibitions on the use of evidence, mutatis mutandis? It seems that the answer depends on identifying the interests underlying non-usability, starting with distinguishing between the safeguarding of legality that protects rights and other more problematic cases, especially when such protected interest does not exist. 6. 2. Legality in the protection of rights 48 Case Costa / Enel (15/07/1964), C-6/64. ECLI:EU:C:1964:66. 49 Case Simmenthal (09/03/1978), C-106/77, ECLI:EU:C:1978:49. More recently: CJEU (24/6/2019), Popławski, C-573/17, ECLI:EU:C:2019:530. 50 For example: CJEU Euro Box Promotion and others (21/12/2021), C-357/2019. ECLI:EU:C:2021:1034. 51 Recently: CJEU Lin (24/07/2023), C-107/23. ECLI:EU:C:2023:606. 450 Riccardo Bianchi REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 There is no question when the legality of the procedure serves to protect fundamental rights 52 . If the due process prescribed by law is not a European interest that is strong enough to impose exclusionary rules (as stated in the previous paragraph), it will at least be valid to exclude instances of antinomies between national and European law. Therefore, nothing prevents the operation of the prohibition on the use of evidence. The Grand Chamber has written words that strongly suggest this direction: when a potential antinomy is hypothesized, it is necessary to verify whether the disapplication would be at odds with the protection of fundamental rights 53 , which is also valid in criminal proceedings within the scope of European law, including investigations (Article 51 of the Charter) 54 . One case is particularly relevant to us, as it specifically concerns exclusionary rules of evidence. The co-defendants encountered an obstacle in their VAT obligations and did not pay them, steering a criminal organization towards tax evasion. They were intercepted illegally (by an incompetent judge who authorized it), but they could not have avoided conviction even without the intercepted elements, which are to be excluded according to the Bulgarian Code. But there was one exception: a defendant who was incriminated solely by inadmissible statements, but the Bulgarian judge saw in his potential acquittal a violation of the Union’s financial interests. Therefore, he referred the preliminary questions. No disapplication is required, as the Court ruled (CJEU Dzivev and others, 2019 55 ). The Bulgarian exclusionary rule implements European principles of legality in legal proceedings, which Articles 52 of the Charter and 2 TEU (rule of law) mandate for the protection of fundamental rights enshrined by the EU. Since interception interferes with the right to private life (Article 7 Charter), it is subject to these requirements, without financial interests prevailing over a national prohibition on the use of evidence that reinforces them. Thus, the resulting evidence is entirely inadmissible, tamquam non esset. 52 For a summary on the importance of fundamental rights, see: Bachmaier Winter, Lorena (2018), “Fundamental Rights and Effectiveness in the European AFSJ”, Eucrim, 1, pp. 56-63. 53 CJEU Lin cit., para. 100. 54 La Rocca, Nadia and Alfredo Gaito (2019), “Il controlimite della tutela dei diritti processuali dell’imputato: visioni evolutive dalle Corti europee tra legalità e prevedibilità”, Archivio penale, 1 (web). 55 Case Dzivev and others (17/01/2019), C-310/16. ECLI:EU:C:2019:30. La prueba ilícita: la razón de ser y el derecho de la Unión Europea 451 REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 6. 3. Problematic hypotheses Conclusions are valid when rules ensure constitutional freedoms; those just developed become insignificant due to normative sophisms lacking valid reasoning. Some examples can be found within the Italian legal system. At the outset of an interrogation, the interviewee is warned about the fact that if they make statements regarding facts concerning another’s liability, they will assume the role of a witness concerning those facts. If such a warning is not given, the Code prescribes the non-usability of the statements and the inadmissibility of the related testimony (Article 64.3-bis). One would need a map to trace the rationale (and reasonableness, Article 3 of the Constitution) behind the rule; what it might be, however, is not known 56 . Nevertheless, intellectual honesty admits the complexity of imagining that the accused could achieve impunity due to a violation of this rule, especially when the accusation concerns offenses against the Union’s financial interests. However, it serves as an excellent theoretical example. Conversely, it may happen that wiretaps play a decisive role, even in this type of proceeding (the Court of Justice addressed such a case not too many years ago: the already mentioned Dzivev judgement). Article 68 of the Italian Constitution requires the authorization of the Member’s respective Chamber in order to intercept their communications. The legislator has leniently interpreted Article 68 and implemented it in a rather peculiar way: if the honorable Member happens to intervene in a conversation that is lawfully intercepted, it is up to the Chamber to decide whether the words may be used (Article 6, L. 140/2003). In this eccentricity, the Constitutional Court identifies profiles of unconstitutionality (ruling 390/2007 57 ), but only with reference to statements that must be used against the non-honorable citizen. The aforementioned Article 6 regulates the fate of incidental eavesdropping, that is, interceptions of conversations in which the intervention of the parliamentarian occurs by sheer chance: the investigators could not have anticipated their involvement, as the third party being wiretapped was not part of the esteemed circle of the honorable member’s usual contacts (had this individual been part of that group, prior authorization from the 56 Cordero, Franco (2012), Procedura penale, Milano, Giuffrè, p. 659. 57 C. cost. nº 390/2007 (ud. 19/11/2007; dep. 23/11/2007). ECLI:IT:COST:2007:390. 452 Riccardo Bianchi REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 Chamber would have been required). Article 6 introduces a discipline that is foreign to Article 68 of the Constitution, which is devised to prevent the judiciary’s persecutory intents against the democratic system, which are unimaginable when it comes to incidental interceptions: the investigators could not have foreseen that intervention. Moreover, the constitutional text sets conditions for “subjecting members of parliament to interceptions”, which means laying a net around the channel through which someone communicates or receives; this latter scenario does not exist in the case of incidental eavesdropping: the net, constructed around a third party and not the parliamentarian, simply captures the latter’s intrusions. Nevertheless, the cited ordinary regulation is concise: to use their words, authorization from the Chamber is required; if denied, the conversations would be excluded as evidence (inutilizzabili), but this outcome could conflict with the financial interests of the Union. Outside of Article 68 of the Constitution, parliamentarians do not enjoy any constitutionally privileged rights compared to ordinary citizens, and Article 6 of L. 140/2003 lies outside of it: it was partially upheld by the Constitutional Court, yet it could be in conflict with the European interests we discussed. The Court of Justice has articulated more sensible words than those often circulating within the bastions of politics: ensuring the protection of the innocent and guaranteeing the fairness of the procedure are the missions of procedural rules; they are, however, unrelated to sophisticated tactics aimed at securing impunity. Specifically: “The Member States must also ensure that the rules of criminal procedure, laid down by national law, permit effective investigation and prosecution of offences linked to such conduct” 58 . In June 2018, the Grand Chamber declared the incompatibility of the Bulgarian procedural rules on case dismissal with the European legal order 59 : a loophole allowed offenders to evade justice, contrary to the protection of the Union’s financial interests (in this case, the charges related to criminal activities involving customs duties). It is complex to determine the consequences of such conflicts when it concerns dismissals and investigation deadlines; it is simpler, however, in the case of the nonusability of evidence: the rule must be set aside. 58 Case Dzivev and others (cited above), para. 29. 59 Case Kolev and others (05/06/2018), C-612/15. ECLI:EU:C:2018:392. La prueba ilícita: la razón de ser y el derecho de la Unión Europea 453 REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 7. THE DANGERS OF JUDICIAL BALANCING 7. 1. Appropriation: rights vs. fact-finding The exclusion of evidence obtained in violation of a fundamental right has faced erosive attacks over the years. Among these attacks is the devotion to proportionality, which jurisprudence appropriates through interpretations that disregard the legislator’s competence (and the Constitutional Court’s role as the guardian of laws). Highlighting the dangers that are hidden by judicial proportionality assessments, as opposed to those prescribed by law, is crucial for European law as well, where proportionality is a relevant concept (consider, for example, the proportionality concerning the use of evidence obtained through a European investigation order 60 , or the admissibility of evidence with specific reference to EPPO proceedings 61 ). STC 136/2000 62 concluded a case stemming from a reckless chase through Madrid’s streets, aimed at settling scores between drug dealers. It reaffirmed the necessity for a search authorization to be justified by presenting facts: Facts and proportionality are the components of justification; if they are lacking, the inviolability of the home is compromised. For the Court, arguing the proportionality of the measure being authorized by the authorities means addressing: 1. suitability, id est the measure’s ability to achieve the intended goal; 2. necessity, id est the insufficiency of less intrusive means; 3. the balance between the sacrifice endured by the right and the expected benefit. The requirement that suitability and necessity must be concretely established is nothing new when it comes to the balancing accepted by the Code. The legislative text has prescribed that rights can be limited only if (1.) the restriction is reasonable and (2.) it is unavoidable; this is stated abstractly, and it is a natural consequence that the existence of these requirements is concretely evaluated. When the judge assesses suitability and necessity, they do not ponder anything. 60 Daniele, Marcello and Ersilia Calvanese (2018), “Evidence gathering” in Roberto Kostoris (ed.), Handbook of European Criminal Procedure, Cham, Switzerland, Springer, p. 368. 61 Brodowski, Dominik (2023), “Admissibility of Evidence in EPPO Proceedings”, New Journal of European Criminal Law, 14, pp. 34-42. 62 STC nº 136/2000 (29th May), nº proc. 77/1996. 454 Riccardo Bianchi REVISTA DE ESTUDIOS EUROPEOS, 85 (2025): 430-463 ISSN 2530-9854 The mystery lies in the third assertion, which seems to be a circumlocution for proportionality in the strict sense, but its manifestations should be found in the law, not in judicial assessments 63 . Codes should determine when a measure is disproportionate by imposing limits: for instance, conducting a search at four in the morning is disproportionate, and the law specifies this. Conversely, asking the judge to evaluate the “balance” is akin to handing them a scale, a tool for weighing interests. Balancing two interests involves determining the cases in which one prevails and those in which the other does, based on circumstances (for example, distinguishing between day and night, serious and minor offenses). If the judge identifies and weighs these circumstances, they are authorized to apply their own evaluation in addition to that of the law. In Spain, this has been legitimized not only by case law 64 but also by a reform. A new design was introduced by Ley Orgánica 13/2015 65 . The reform has restored the arsenal of technological investigative measures: wiretapping; access to stored electronic data; searches of computer devices (including spyware); operations by undercover agents online; tracking devices; video surveillance. The new Chapter IV (Title VIII, Book II) introduces this fresh regulation with general provisions on the innovative means of evidence gathering, and Article 588-bis-a proclaims the guiding principles: among them, we find proportionality. Driven by interpretative assistance needs, the provision outlines the parameters within which it must be sought: it must exist between the sacrifice of the fundamental right and the competing public and/or third-party interests. What about the assessment? It is made by considering “all the circumstances of the case”, with specific regard to public interest, including the gravity of the offense, its social impact, the technological scope, the intensity of the evidence, and the significance of the result pursued by the measure. We have thus identified the elements involved in discretionary decision-making. 63 The proportionality is recognized as an intermediate thesis by López Barja de Quiroga, Jacobo (2019), Tratado de derecho procesal penal. 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