JUDGMENT NO. 64

YEAR 2026

ITALIAN REPUBLIC

IN THE NAME OF THE ITALIAN PEOPLE

THE CONSTITUTIONAL COURT

composed of:

President: Giovanni AMOROSO;

Justices: Francesco VIGANÒ, Luca ANTONINI, Stefano PETITTI, Angelo BUSCEMA, Emanuela NAVARRETTA, Maria Rosaria SAN GIORGIO, Filippo PATRONI GRIFFI, Marco D’ALBERTI, Giovanni PITRUZZELLA, Antonella SCIARRONE ALIBRANDI, Massimo LUCIANI, Maria Alessandra SANDULLI, Roberto Nicola CASSINELLI, Francesco Saverio MARINI,

has pronounced the following

JUDGMENT

in the proceedings regarding the constitutionality of Article 34, paragraph 2, of the Code of Criminal Procedure, initiated by the Ordinary Court of Siena, Criminal Section, sitting as a single judge, in the criminal proceedings against A. C., pursuant to the referral order of March 25, 2025, registered as no. 78 of the 2025 register of orders and published in the Official Gazette of the Republic, no. 19, first special series, of the year 2025.

Having regard to the intervention of the President of the Council of Ministers;

having heard the reporting Justice Marco D’Alberti in the chambers on February 23, 2026;

having deliberated in the chambers on February 23, 2026.

Legal Reasoning (Facts)

1.– By order dated March 25, 2025, registered as no. 78 of the 2025 register of orders, the Ordinary Court of Siena, Criminal Section, sitting as a single judge, raised, with reference to Articles 24(2), 111(2), and 117(1) of the Constitution—the latter in relation to both Article 6(1) of the European Convention on Human Rights and Article 14(1) of the International Covenant on Civil and Political Rights—questions of constitutionality regarding Article 34(2) of the Code of Criminal Procedure, insofar as it "does not provide that a judge who has issued, against another person charged with the same offence, a decision pursuant to Article 554-ter, paragraph 3, of the Code of Criminal Procedure, may not participate in the subsequent summary trial (giudizio abbreviato) against a person charged with the offence under Article 588 of the Penal Code.”

The referring judge states that he is called upon to decide on a request for a summary trial submitted by one of the co-defendants for the offence of affray (rissa) under Article 588 of the Penal Code, having already ordered, for other co-defendants in the same offence, the continuation of the proceedings before the trial judge, pursuant to Article 554-ter of the Code of Criminal Procedure.

The referring judge clarifies that the defendant was brought to trial to answer, jointly with other persons, for the offence of aggravated affray; at the preliminary hearing, the defendant’s counsel requested that the trial be settled pursuant to Article 438 of the Code of Criminal Procedure, subject to supplementary evidence consisting of an expert report aimed at assessing the defendant’s mental capacity at the time of the event. The referring judge reports having admitted the chosen alternative procedure and, having separated the proceedings, ordered the continuation of the trial against the other defendants before a different judge, in the absence of requests for alternative settlements, pursuant to Article 554-ter(3) of the Code of Criminal Procedure.

The referring judge reports having submitted a declaration of abstention from the proceedings, also pursuant to Article 36(1)(h) of the Code of Criminal Procedure, in which he highlighted having ordered, pursuant to Article 554-ter(3) of the Code of Criminal Procedure, the continuation of the trial against persons charged with the same historical fact contested to the defendant, thereby making a merit-based assessment of the accusation formulated by the Public Prosecutor. The referring judge further specified that, as the offence requires necessary participation (concorso necessario), the judgment regarding the merits of the accusation against the defendant could not be considered subject to an autonomous and separate assessment from the decision already taken under Article 554-ter(3) regarding the co-defendants, resulting in the duty to abstain; however, the President of the Section did not accept the declaration of abstention and ordered the immediate return of the case files to the referring judge for the continuation of the trial, deeming the decision previously adopted against the co-defendants to lack decisional nature.

The referring judge therefore deduced that he is called upon to render a "decision on the merits,” such as a judgment concluding a trial held under the summary procedure, against a person charged with an offence requiring necessary participation, despite having already issued the order pursuant to Article 554-ter(3) of the Code of Criminal Procedure against the other persons charged with the same offence.

2.– Given the above, the referring judge observes that the institute of incompatibility concerns situations of prejudice to the impartiality of the judge and expresses fundamental values of jurisdiction, such as neutrality and impartiality, which are in turn linked to the guarantee of a fair trial. This institute is aimed at preventing excessive subjectivity in judgment and safeguarding impartiality, both of the judge and of the choice made between alternative decisional hypotheses; in this perspective, the constitutional and supranational references for the institute of judicial incompatibility can be found in Articles 111(2), 24(2), and 117(1) of the Constitution, the latter in relation to both Article 14(1) of the ICCPR and Article 6(1) of the ECHR, as interpreted by the case law of the European Court of Human Rights.

The referring judge cites constitutional case law, which has stated that the institute of incompatibility is based on the identification of a catalogue of prejudicial situations, categorized ex ante and in the abstract, including the exhaustive hypotheses in which the impartiality of the judge is compromised per se, for the mere fact that the relative conditions of these general and abstract cases occur (referencing the judgments of this Court no. 179 of 2024 and no. 308 of 1997).

The order also references the judgments of this Court no. 371 of 1996 and no. 241 of 1999, concerning "particular hypotheses” in which the activity the judge has performed in a previous proceeding determines situations of prejudice to his impartiality in the subsequent proceeding against another or other co-defendants, assessable ex ante and in the abstract. In particular, the referring judge highlights that in judgment no. 371 of 1996, this Court clarified that a situation of judicial incompatibility exists where the position of the co-participants in the same offence, already the subject of a previous assessment, constitutes an essential element for the very configurability of the offence contested to the other co-participants, as happens in cases of multi-party offences.

3.– The referring judge then notes that, in the case of a multi-party offence, the identification of a co-participant and the "merit” evaluation of the accusatory hypothesis constitute essential moments for the very configurability of the offence, to the point that any such assessment, referring to some originally co-defendant subjects, necessarily includes an assessment regarding the participation of other co-participants. Consequently, in all cases where the position of one of the co-participants constitutes an essential element for the very configurability of the offence contested to the others, "as happens in every offence with necessary participation,” the impartiality of the judge could only be considered compromised ex ante and at the root, i.e., in a general and abstract way, in cases where the judge, after having made a decision on the "merits” of the offence attributed to a defendant, is then called upon to judge another co-participant of the same multi-party offence.

4.– In the present case, in ordering the continuation of the trial pursuant to Article 554-ter(3) of the Code of Criminal Procedure in relation to a multi-party offence and only for some of the co-defendants, the judge’s conviction would have been formed not only on the "merits” of the criminal action exercised against them, but also, albeit incidentally, on the position of the remaining participant, who remained third and extraneous to the proceedings, having therefore already evaluated the position of the latter as a necessary participant in the same offence.

Indeed, according to what has been affirmed by this Court, the merely procedural nature of the deliberation adopted by the judge of the preliminary hearing pursuant to Article 554-ter(3) of the Code of Criminal Procedure should be excluded, as said decision implies evaluations that properly involve the "merits” of the accusation formulated against a defendant (referencing the judgment of this Court no. 179 of 2024).

Therefore, according to the referring judge’s perspective, the issuance of the order pursuant to Article 554-ter(3) of the Code of Criminal Procedure against some of the participants in a multi-party offence, such as the crime under Article 588 of the Penal Code, possesses a "prejudicial force” such as to disturb the fundamental values of the neutrality and impartiality of the judge who is then called upon to participate in the summary trial proceedings brought against another participant in the same offence. In said hypothesis, the prejudicial effect for the impartiality of the criminal judge would be identifiable ex ante and in the abstract, entailing the incompatibility of the same to rule on the responsibility of the other necessary co-participants; furthermore, due to the exceptional and exhaustive nature of the cases provided for by Article 34(2) of the Code of Criminal Procedure, an analogical extension of the indicated hypotheses, such as to include the hypothesis of the present proceeding, would not be concretely practicable.

5.– The President of the Council of Ministers, represented and defended by the State Attorney’s Office, intervened in the proceedings, requesting that the questions of constitutionality be declared inadmissible or, in any case, unfounded.

Regarding the first point, the intervenor argued that the referring judge, despite having also indicated Article 24(2) of the Constitution as a constitutional parameter violated by the challenged provision, did not subsequently specifically argue regarding the doubt of constitutionality with respect to said provision.

Furthermore, also under the aspect of the admissibility of the questions, the referring judge did not specify the number of co-defendants involved in the multi-party offence that is the subject of the trial, whose consideration would be essential to evaluate the eventual incompatibility of the judge: in fact, "only where the position of one of the co-participants constituted an essential element for the configurability of the offence contested to the other co-participants, could the assessment already made of the position of even one of the defendants have relevance for the purposes of the existence of a possible incompatibility of the judge,” because only where it was impossible to "disregard the latter position for the purposes of ascertaining the responsibility of the others could a ‘judge’s incompatibility’ be said to exist” (referencing the judgment of this Court no. 371 of 1996).

To deem a situation of incompatibility to exist, the mere observation, in the abstract, of the nature of the multi-party offence would not be sufficient, but it would be necessary that the judgment already rendered conditions the possibility of reaching a different decision for the individual defendant subjected to trial, a hypothesis to be excluded where more than three people had concretely participated in the contested affray.

6.– On the merits, the President of the Council of Ministers concluded for the lack of foundation of the questions, for the same reasons adduced in support of the exception of inadmissibility, as it does not result in any way from the case documents that the affray was carried out by only three individuals.

In the absence of this condition, no situation of prejudice to the judge who has already ruled on the position of some co-defendants of the same offence could be detected.

Legal Reasoning (Law)

7.– The Court of Siena, Criminal Section, sitting as a single judge, with the order indicated in the epigraph (reg. ord. no. 78 of 2025) has raised, with reference to Articles 24(2), 111(2), and 117(1) of the Constitution—the latter in relation to both Article 6(1) of the ECHR and Article 14(1) of the ICCPR—questions of constitutionality regarding Article 34(2) of the Code of Criminal Procedure, in the part where it does not provide that a judge who has issued, against another person charged with the same fact, the order pursuant to Article 554-ter(3) of the Code of Criminal Procedure, may not participate in the subsequent summary trial against a person charged with the offence under Article 588 of the Penal Code.

7.1.– The referring judge, having premised that he ordered, as the judge of the preliminary hearing, the separation of the proceedings and the continuation of the trial—before a different judge—against some defendants of an affray, pursuant to Article 554-ter(3) of the Code of Criminal Procedure, highlighted that he then admitted the summary trial requested by one of the co-defendants, conditioned on the acquisition of an expert report. Called to conclude the summary trial, he formulated a request for abstention, believing that he had already evaluated on the merits, when ordering the continuation of the trial against the co-defendants, also the position of the defendant admitted to the summary trial, in consideration of the nature of the multi-party offence of the contested fact.

7.2.– Having had the cited request for abstention rejected by the President of the Section, the referring judge raised questions of constitutionality regarding Article 34(2) of the Code of Criminal Procedure, in the part where it does not provide for the incompatibility to judge in a summary trial one of the co-defendants of an affray, for the judge who, at the outcome of the preliminary hearing, has previously ordered the continuation of the trial against the participants in the same offence.

The referring judge observed that the order provided for by Article 554-ter(3) of the Code of Criminal Procedure presupposes an assessment not merely formal, but of merit, on the consistency of the accusatory hypothesis and, as such, is suitable to prejudice the impartiality and neutrality of the judge at the time of the subsequent decision of the summary trial requested by one of the co-defendants, with consequent violation of the indicated parameters.

8.– Preliminarily, the exceptions of inadmissibility raised by the President of the Council of Ministers must be examined.

8.1.– In the first place, the exception of inadmissibility for failure to indicate the reasons for which Article 24(2) of the Constitution is considered violated is unfounded.

From the overall content of the referral order, it is evident that such a constitutional parameter, even if only formally indicated in the reasoning of the provision, was nonetheless invoked as it is potentially harmed by the prejudice to the values of the impartiality and neutrality of the judge, to whose protection, as repeatedly stated by this Court, the discipline of the challenged incompatibility is preordained (judgments no. 212 and 190 of 2025, no. 209 and no. 74 of 2024).

8.2.– The exception of inadmissibility for failure to indicate the "number of co-defendants involved in the so-called multi-party offence” that is the subject of the main proceedings is also unfounded.

According to the constant orientation of this Court, questions of constitutionality are admissible when the referral order is argued in a way that allows the "external” control of relevance through a non-implausible motivation of the logical path followed and the reasons for which the referring judge claims to have to apply the challenged provision in the main proceedings (among many, judgments no. 23 and no. 21 of 2026, no. 213 of 2025, no. 179 of 2024 and no. 94 of 2023).

The referring judge maintained that, having expressed himself in the sense of the continuation of the trial against some co-defendants in an affray, which integrates a multi-party offence, for that reason alone he had become incompatible to rule, subsequently, on the co-defendant who had requested to be judged with the summary procedure.

Hence the relevance of the questions of constitutionality as prospected, while the correctness of the hermeneutic premises from which the referring judge moves is a profile that pertains to the merits (judgments no. 38 and no. 36 of 2025, no. 119 and no. 73 of 2023).

9.– On the merits, the questions are unfounded.

According to the constant case law of this Court, the rules on the incompatibility of the judge, deriving from acts performed in the proceedings, are placed to protect the values of the neutrality and impartiality of the jurisdiction, guarded by Articles 3, 24(2), and 111(2) of the Constitution, being aimed at avoiding that the decision on the merits of the case can be or appear conditioned by the force of prevention—that is, by the natural tendency to confirm a decision already taken or maintain an attitude already assumed—stemming from evaluations which the judge has previously been called upon to make in order to the same res iudicanda (among many, judgments no. 182 of 2025, no. 209, no. 179 and no. 74 of 2024, no. 16 of 2022 and no. 183 of 2013).

The need to provide for a hypothesis of incompatibility, by virtue of the mentioned principles, exists when the same judge has already carried out, in relation to the same judgment, a "prejudicial activity,” and is again called upon to perform a decisional task in a "prejudiced seat” by his own previous activity.

For a prejudice to be affirmed, according to constitutional case law, the judge must have been called upon to make an evaluation of acts previously performed, for the purposes of taking a decision (it not being sufficient to have had knowledge of the acts themselves); such evaluation must pertain to the merits of the accusatory hypothesis (and not to the mere conduct of the trial); finally, the previous evaluations must be located in a different phase of the proceedings (among the most recent, judgments no. 212, no. 190 and no. 182 of 2025, no. 209 and no. 179 of 2024).

This Court has clarified on several occasions that the rigor of the regime of incompatibilities cannot, however, determine excessive organizational burdens for the jurisdiction, so that the relative rules must be applied only when there is a real and effective need for prevention of the deviation of the administration of justice from the path of neutrality and impartiality. It must, in fact, be considered that "in any decision-making process, as dynamic intellectual activity, and not static, the holder of the competent body matures its conviction in itinere, which can therefore well be said to be ‘of progressive formation’” (judgment no. 182 of 2025).

It is for this reason that incompatibility does not find application when the previous abstractly "prejudicial” evaluations are placed in the same phase of the proceedings (judgments no. 179 and no. 93 of 2024, no. 172 and no. 91 of 2023, no. 64 of 2022).

Within each of the phases into which the judgment is divided—understood as ordered sequences of acts that can imply incidental appraisals, even on the merits—the need for the continuity of the same must in fact be preserved, otherwise resulting in an excessive fragmentation of the proceedings, which would imply the need to have, for the same phase of the judgment, as many different judges as there are acts to be performed (judgments no. 7 of 2022, no. 66 of 2019 and no. 18 of 2017).

9.1.– In the case subject of the main proceedings, the activity which according to the referring judge gave rise to the situation of incompatibility is constituted by the order with which, at the outcome of the preliminary hearing, the continuation of the trial was ordered before the—different—trial judge, pursuant to Article 554-ter(3) of the Code of Criminal Procedure.

The preliminary hearing, as a chamber hearing with the necessary participation of the public prosecutor and the defendant’s counsel (Article 554-bis(1) of the Code of Criminal Procedure), was introduced into the proceedings before the court sitting as a single judge by Article 32 of Legislative Decree no. 150 of October 10, 2022 (Implementation of Law no. 134 of September 27, 2021, delegating the Government for the efficiency of the criminal trial, as well as regarding restorative justice and provisions for the swift definition of judicial proceedings), as a mandatory junction between the preliminary investigations and the trial, in order to allow, even in cases of direct summons to trial, a preventive screening regarding the need for the continuation of the process.

In this phase, the judge’s control over the imputation takes place, and the parties’ requests for alternative definition of the judgment can be presented: the request for summary trial, the request for application of an agreed penalty, the request for suspension of the proceedings with probation, and the request for obliteration are, in fact, proposed, under penalty of forfeiture, before the hearing concludes, alternatively, with the decree of fixing the trial hearing pursuant to Article 555 of the Code of Criminal Procedure or with the judgment of no grounds for proceedings pursuant to Article 554-ter(1) of the Code of Criminal Procedure.

According to the last-cited provision, the trial closes with a judgment of no grounds for proceedings if, on the basis of the transmitted documents, there is a cause that extinguishes the offence or for which the criminal action should not have been initiated or should not have been continued, as well as if it results that the fact is not provided for by law as an offence or that the fact does not exist or that the defendant did not commit it or that the fact does not constitute an offence or that the defendant is not punishable for any cause.

Furthermore, "[t]he judge pronounces a judgment of no grounds for proceedings also when the elements acquired do not allow a reasonable prediction of conviction,” in application of the same criterion provided for by Article 425(3) of the Code of Criminal Procedure, as amended by Article 23(1)(l) of Legislative Decree no. 150 of 2022, for the judge of the preliminary hearing.

If, instead, the judge of the preliminary hearing believes, at the outcome of the preliminary screening on the accusatory hypothesis, that the acquired elements allow "a reasonable prediction of conviction” and there are no grounds for acquittal, he fixes for the continuation of the trial the date of the trial hearing before a "different judge” and orders the return of the public prosecutor’s file (Article 554-ter(3) of the Code of Criminal Procedure).

9.2.– This Court has already pronounced, with judgment no. 179 of 2024, on the prejudicial value of the order with which, at the outcome of the preliminary hearing, the continuation of the trial is ordered, affirming that "[t]he decisional activity that the judge is called upon to perform in the preliminary hearing, summarized in the evaluations subject of the measures pursuant to Articles 554-bis and 554-ter of the Code of Criminal Procedure, [...] characterizes such hearing as a prejudicial seat of the subsequent decisional phase, in that the preliminary hearing judge exercises a penetrating screening of the merits of the accusation.” In this regard, it was noted that the evaluation made in such seat, on the basis of the documents of the preliminary investigations, extends from the verification of the correspondence of the imputation to the investigation documents, also in reference to aggravating circumstances, to the ascertainment of the existence of causes of improcedibility of the criminal action, of non-punishability, and of acquittal on the merits, to the adoption of a decision, on the basis of the documents, regarding the existence of the reasonable prediction of conviction, which creates an evident risk of conditioning the subsequent decisional phase.

9.3.– Once the potentially conditioning nature of the decision taken pursuant to Article 554-ter(3) of the Code of Criminal Procedure is established, it must be noted that, in the case under examination, the referring judge, contextually to the continuation of the trial against the co-defendants, ordered the separation of the trials, in order to provide in the forms of the summary procedure (in the species conditioned on the completion of the expert report) against the defendant.

This entails that, in the case under examination, a situation of prejudice to the impartiality occurred within the same proceedings would not be relevant, since, as already noted by this Court in similar cases, the judge is faced with "different proceedings, destined, after the separation, some to the subsequent trial definition and others to the treatment in the forms of the summary judgment” (order no. 86 of 2013).

In such hypotheses, the commonality of the imputation is matched by a plurality of conducts distinctly attributable to each of the participants, such as to form the subject of autonomous evaluations, separable one from the other, under both the material and psychological profile (ex multis, judgments no. 439 of 1993 and no. 186 of 1992).

In the same sense, the legitimacy case law has pronounced on several occasions, affirming that it does not constitute a cause of incompatibility pursuant to Article 34 of the Code of Criminal Procedure for the preliminary hearing judge who must examine the request for indictment of a participant in the offence to have issued the decree ordering the trial against another participant in the same offence, separately judged (Court of Cassation, Fifth Criminal Section, judgment December 3, 2020-January 13, 2021, no. 1215).

9.4.– It is true that, with reference to the hypotheses of offences with necessary participation, in which for the completion of the criminal hypothesis the participation of a minimum number of people is required, this Court has affirmed that, in the case in which the position of one of the participants constitutes an essential element for the very configurability of the offence contested to the other participants, the evaluation of such position, from which it was not possible to disregard for the purposes of the ascertainment of the responsibility of the defendants, can constitute a reason for incompatibility in the subsequent trial against the same participant (judgment no. 371 of 1996).

For the affirmation of a situation of incompatibility, therefore, the mere observation, in the abstract, of the nature of the multi-party offence for which one is proceeding is not sufficient, it being necessary, instead, that the judgment already rendered conditions, in concreto, the possibility of reaching subsequently a different decision for the individual defendant subjected to trial.

A similar situation is recognizable, by definition, in the case in which, without the participation of the person against whom one is proceeding separately, the offence cannot be said to be perfected, because the minimum number of participants necessary for that purpose would be missing; it does not recur, instead, in the case in which the offence can be said to be integrated even without the participation of the subject still to be judged, since in that case the evaluation of his conduct would not be essential for the ascertainment of the existence of the criminal hypothesis.

In such a case, the incompatibility could be recognized not in the face of the abstract nature of the multi-party offence, but only if the defendant’s position had been effectively already evaluated by the judge in deciding on the co-participants.

9.5.– However, in the referral order, the referring judge limited himself to reporting that he was proceeding against the defendant for the offence under Article 588 of the Penal Code (affray), with necessary participation, having already ordered the continuation of the trial against the "remaining” persons charged with the same offence.

The unconstitutionality of the lack of provision of incompatibility was, therefore, supported on the basis of the abstract configuration of the hypothesis, noting that "in all cases where the position of one of the participants constitutes an essential element for the very configurability of the offence contested to the other participants, as happens in every offence with necessary participation, the impartiality of the judge can only be considered compromised ex ante and at the root, i.e., in a general and abstract way.”

Such an interpretative premise does not find comfort in constitutional case law which, even in these hypotheses, links the incompatibility of the judge not to the abstract hypothesis of the offence, but to an already accomplished evaluation in concreto of the defendant’s position (judgment no. 371 of 1996; orders no. 86 of 2013 and no. 105 of 1999).

On the other hand, in the specific case, the position of the defendant to be judged separately was not essential for the integration of the criminal hypothesis of affray, which exists when at least three people have participated. Indeed, from the documents of the main proceedings, it results that the persons for whom the continuation of the trial had already been ordered were five and that the summary trial was requested by one of the six co-defendants.

Therefore, the offence could be said to be integrated in any case even without the participation of the subject still to be judged, with the consequence that the evaluation of his conduct does not constitute an essential element for the very configurability of the criminal hypothesis contested to the other participants, not being able, therefore, to recognize the cause of incompatibility identified in similar hypotheses by constitutional case law.

The questions must, therefore, be declared unfounded.

for these reasons

THE CONSTITUTIONAL COURT

declares the questions of constitutionality of Article 34(2) of the Code of Criminal Procedure, raised, with reference to Articles 24(2), 111(2), and 117(1) of the Constitution—the latter in relation to Article 6(1) of the European Convention on Human Rights and Article 14(1) of the International Covenant on Civil and Political Rights—by the Ordinary Court of Siena, Criminal Section, sitting as a single judge, with the order indicated in the epigraph, to be unfounded.

So decided in Rome, at the seat of the Constitutional Court, Palazzo della Consulta, on February 23, 2026.

Signed:

Giovanni AMOROSO, President

Marco D’ALBERTI, Reporter

Roberto MILANA, Director of the Chancellery

Deposited in the Chancellery on April 30, 2026

The anonymized version is consistent, in the text, with the original.