F. Principle of legality (nullum crimen, nulla poena sine lege) International jurisprudence uniformly emphasizes the importance of the principle of nullum crimen, nulla poena sine lege, according to which criminal conduct must be defined in law before an offense can be committed, and with sufficient precision so as to prevent arbitrary enforcement. In this connection, it should be noted that the Covenant (at article 4) includes among its non-derogable provisions article 15, under which no one shall be held guilty of any criminal offence on account of any act which did not constitute a criminal offence at the time it was committed. United Nations The Committee is concerned that the relatively broad definition of the crime of terrorism and of membership of a terrorist group under the State party's Criminal Code may have adverse consequences for the protection of rights under article 15 of the Covenant, a provision which significantly is nonderogable under article 4, paragraph 2. --CCPR/CO/77/EST, para. 8 (2003). ***** The Committee is particularly disturbed by the adoption in 1992 of law No. 97 on terrorism, which contains provisions contrary to articles 6 and 15 of the Covenant. The definition of terrorism contained in that law is so broad that it encompasses a wide range of acts of differing gravity. The Committee is of the opinion that the definition in question should be reviewed by the … authorities and stated much more precisely, especially in view of the fact that it enlarges the number of offences which are punishable with the death penalty. The Committee underscores that according to article 6, paragraph 2 of the Covenant, only the most serious crimes may lead to the death penalty. --CCPR/C/79/Add.23, para. 8 (1993); see also CCPR/CO/76/EGY, para. 16 (2002). European Court of Human Rights The Court recalls that the guarantee enshrined in Article 7, which is an essential element of the rule of law, occupies a prominent place in the Convention system of protection, as is underlined by the fact that no derogation from it is permissible under Article 15 in time of war or other public emergency. It should be construed and applied, as follows from its object and purpose, in such a way as to provide effective safeguards against arbitrary prosecution, conviction and punishment…. 63