The principle of nulla poena sine lege, insofar as it applies to general criminal law, is enshrined in several national constitutions and international instruments (see Article 7, paragraph 1, of the European Convention on Human Rights). However, when applied to international criminal law and international humanitarian law, the same instruments often allow for the ex post application of the law. See Article 7(2) of the ECHR, which states that Article 7(1) “is without prejudice to the conviction and punishment of a person for an act or omission which, at the time it was committed, was punishable under the general principles of law recognised by civilised nations”.  Since the Prague trials, criminal law has included prohibitions of international criminal law in addition to those of national law.  Thus, it is possible to prosecute persons such as Nazi war criminals and GDR officials responsible for the Berlin Wall, even if their acts were authorized or even ordered under national law. Moreover, when dealing with such cases, courts tend to follow the law of the time to the letter, even in regimes where the law, as drafted, is generally ignored in practice by its own authors. [ref. needed] Romans 5:13 (For until the law is sin in the world; but sin is not attributed if there is no law. Nullum crimen sine lege is sometimes called the principle of legality. It is also interchangeable with “nullum poena sine lege”, which translates to “no punishment without law”. Nullum crimen sine lege means in Latin “no crime without law”.
However, some jurists criticize this because in the legal systems of continental Europe, where the maxim was first developed, “criminal law” was generally understood as statutory criminal law in order to provide the individual, considered a fundamental right, with a guarantee that he will not be prosecuted for an act or omission that is not considered a crime under the laws adopted by the legislators in force. then. the act or omission and only the penalties in force at the time of the offence are applied. [ref. needed] Even bearing in mind that certain acts are prohibited by general principles of international law, critics point out that a prohibition in a general principle does not constitute justification for a crime and that the rules of international law do not provide for specific sanctions for violations. While treaties established the principle of the NCSL, war crimes cases have shaped and defined the application of the NSCL in international criminal law. The International Criminal Tribunal for the former Yugoslavia (ICTY) addressed this issue in its first trial. In the case of The Prosecutor v. Tadić, Case No. IT-94-1-T, Defence motion for interloxiary appeal on jurisdiction, 2 October 1995, the defence argued that the accused could not be tried for violations of crimes against humanity because the definition of this crime applied to international armed conflicts. The application of this definition to internal armed conflicts would violate the principle of the NCSL. The question of jurisdiction can sometimes contradict this principle.
For example, customary international law allows pirates to be prosecuted by any country (applying universal jurisdiction), even if they have not committed any crime in the territory covered by that country`s law. A similar principle has emerged in recent decades with regard to crimes of genocide (see genocide as a crime under domestic law); and United Nations Security Council Resolution 1674 “reaffirms the provisions of paragraphs 138 and 139 of the 2005 World Summit Outcome on accountability for the protection of populations from genocide, war crimes, ethnic cleansing and crimes against humanity,” even if the State in which the population is attacked does not recognize such attacks as a violation of domestic law. It seems, however, that universal jurisdiction should not be substantially extended to other crimes in order to satisfy nulla poena sine lege. For the law operates anger: for where there is no law, there is no transgression. Nullum crimen sine lege is the principle of criminal law and international criminal law according to which a person cannot or should not be punished criminally, except for an act that was criminalized by law before the act. This idea is also reflected in laws that require crimes to be published in a clear legal text. Romans 1:17 For in it the righteousness of God is revealed from faith to faith; as it is written: The righteous shall live by faith. One of the complexities is the legislative power of judges under the common law. Even in civil law systems that do not allow judicial law, it is not always clear when the function of interpreting criminal law ends and when judicial legislation begins.
More recently, in September 2011, the Pre-Trial Chamber concluded in Case 002 that only certain forms of joint criminal enterprise (JEC) existed in customary international law at the applicable time alleged in the final order. IENG Sary case, Decision on the applicability of a joint criminal enterprise, 12 September 2011. The Pre-Trial Chamber decided that while the liability of the JCE I and JCE II companies would have been sufficiently accessible and foreseeable for the defendants in 1975, there was insufficient evidence of consistent State practice by the respondents with respect to JCE III at the time they committed the alleged acts. The Chamber reviewed the Convention on Terrorist Bombings and the Rome Statute of the ICC, sources used by the ICTY in the Tadić case to establish the legality of JSS III. These two sources did not exist when the alleged acts were committed in Cambodia from 1975 to 1979. Thus, the Pre-Trial Chamber was “unable to discern in Cambodian law, which was applicable at the material time, a provision that could have been communicated to the accused that such an extended form of responsibility is also punishable”. As a result, JCE was limited as a type of liability due to NCSL. More recently, the Extraordinary Chambers in the Courts of Cambodia (ECCC) considered the application of the NCSL in Case 002. The tribunal declared that a crime charged before the ECCC must have existed at the time it was committed under national, international or customary law.
IENG Sary case, decision on IENG Sary`s appeal against the final decision, 11 April 2011. The Pre-Trial Chamber decided that the accused could be tried for genocide and crimes against humanity because they were part of customary international law until 1975 and because Cambodia was bound by the Geneva Conventions, to which it was then a party, and was therefore under an obligation not to commit serious breaches of that Convention. The Appeals Chamber also stressed the importance of the NCSL principle, noting that “the only reason the authors had stated that the International Criminal Court should apply customary international law was to avoid a violation of the principle of nullum crimen sine lege if a party to a conflict failed to comply with a particular treaty.” It stipulated that the ICTY would maintain the NCSL as customary law and that contracts would apply to determine whether the NCSL principle had been respected. The Appeals Chamber noted that this nexus requirement had been removed from the definition of crimes against humanity in the Nuremberg Charter and that “the obsolescence of the nexus requirement is evidenced by the international conventions on genocide and apartheid, both of which prohibit certain types of crimes against humanity, regardless of any link to armed conflict.” This principle is codified in international treaties.