It is noted that in order to establish the content of the right to defense, it is necessary to study the interpretation of the right to defense in the practice of national courts. The list of the main circumstances that were considered by the European Court of Human Rights in the decisions against Ukraine in the context of the violation of the right to defense was determined. The inexhaustibility of the circumstances that may constitute a violation of the right to defense, which are the result of judicial discretion, is emphasized; judicial discretion refers to the judge's power to make decisions based on his individual judgment, guided by principles of justice and law. It was determined that the consequences of judicial discretion are determined by its compliance with the requirements of the law, motivation, justice and objectivity. According to the results of the study of the decisions of national courts - resolutions of the CCS of the Supreme Court, it was established that the CCS of the Supreme Court gave an assessment as a violation of the right to defense in the following cases: conducting an investigative action; consideration of the case in the appellate procedure in the absence of the convicted person, who was a minor at the time of the crime, and his lawyer; failure to ensure the participation of a defense attorney at all stages of court proceedings against a person convicted of committing particularly serious crimes, including during the review of court decisions based on newly discovered circumstances; consideration in the court of appeals of the prosecutor's appeal, in which the question is raised about the deterioration of the condition of the convicted person, in the absence of the latter, or in the absence of the defendant who is in custody, as well as his defender, who had not previously participated in this criminal proceeding; the trial in the appeals court was started without finding out whether the convicted person and his defense attorney were properly notified of the date and time of the hearing, holding a hearing in the appeals court without the participation of the defense attorney who was not properly notified of the hearing, including in those cases when the court unreasonably ignores the request of the defense party to postpone the court session; holding a trial in a court of first instance or appellate instance with the participation of a person who, due to mental disabilities, is unable to fully exercise his rights, in the absence of a defense attorney, or the absence of verification of the need to ensure the mandatory participation of a defense attorney in criminal proceedings against persons who, due to mental or physical disabilities defects are not able to fully realize their rights.