The principle of legality is to guarantee and protect legal certainty. Although it is used throughout the legal system, it is gaining importance in the criminal, administrative and tax fields. Thus, from a fiscal point of view, it excludes certain sectors and matters from administrative regulation and acts as a technique protecting the rule of law. For example, the creation, modification and abolition of taxes can only be done by law. The principle of legality, as well as other general principles of law, is at the origin and basis of the rules. General principles take precedence over other sources of law. They are the basis of positive law. According to the principle of legality in criminal law: The importance of the principle of legality is undisputed in all areas, but especially in administrative law. Among other things, because according to this principle, the administration must adhere to a hierarchical legal system. Within the framework of the principle of legality, it acts in conjunction with the principle of the general interest, according to which the private interest must give way to the public or social interest, and with the principle of the separation of powers, according to which public authority is divided into bodies with specific and limited functions for each of them.
FJ. III.4. «According to SC 440/2003-R of 8 April, although the principle of legality in its original configuration meant «a guarantee by which no act could be considered punishable if a law had not declared it punishable before being committed, nor a penalty that had not been previously provided for by law (…) However, it should be clarified that the content of the principle, in its modern configuration, what art. 16.IV CPE, is not limited to the criminal guarantee described, but covers two other guarantees, namely: a. guarantee of jurisdiction (nullapoena sine juditio); No one may be sentenced to punishment without having been heard and brought to justice in accordance with the rules of criminal procedure and on the basis of a final judgment of a competent authority. This ensures that, according to the case-law of the Court of Justice, it is applicable to both the judicial and administrative spheres (hence SSCC 128/2001-R, 347/2001-R and 378/2002-R, among others). b. guarantee of good performance; Subsequently, the criminal sanction (penalty and/or security measure) must be enforced in accordance with the enforceable criminal title issued under specific legislation (laws and regulations); It is the rules that characterize this enforceable title, and it is in this context that the criminal sanction must be enforced; which means that any change in the amount, nature or form of enforcement of the sentence which results in a hardening or limitation of the rights of the sentenced person is unlawful … ». The principle of legality is set out in Article 116.II of the CPE, where it provides that «any sanction shall be based on a law prior to the offence», and in Article 117.I in its procedural aspect, which provides that «no one may be convicted without having been heard and convicted in due process. No one shall be liable to a criminal sanction which has not been imposed by a competent judicial authority in an enforceable sentence. The principle of legality is to give precedence to the law over any activity or function of public authority.
In general, this implies that all authorities and citizens are subject to the law and can only do what is or is not prohibited by law. The principle of legality is associated with other general principles of law. The main application of the principle of legality in administrative law concerns its power to impose penalties. This implies that the attribution of the public administration to the sanction can only be achieved by laws. This guarantee, notwithstanding the legal certainty it implies, consists in the obligation for any public authority to comply with the legal provisions governing its activities and the powers conferred on it by law when issuing an order or warrant concerning a person in his person or in his rights, that is to say: The guarantee of legality essentially presupposes: that the authorities strictly respect the law in their procedures and decisions, which in any way concern persons or their rights. Any change in the scope, nature or form of enforcement of the sentence which results in a hardening or limitation of the rights of the sentenced person violates the principle of legality in its elements of judicial guarantee and enforcement. SCP 2159/2013 reaffirms the case law of the Ten-Year Constitutional Court of SC 0440/2003-R, in which it was stated that the modern form of the principle of legality includes two essential guarantees: «a. guarantee of jurisdiction (nullapoena sine juditio); According to which no one may be sentenced to a sanction without having been heard and brought to justice in accordance with the rules of criminal procedure and on the basis of a final judgment of the competent authority and b.
performance guarantee; Subsequently, the criminal sanction (penalty and/or security measure) must be enforced in accordance with the enforceable criminal title issued under specific legislation (laws and regulations); These are the rules that characterize this enforceable title, and it is within this framework that the criminal sanction must be enforced; which means that any change in the amount, nature or form of enforcement of the sentence that results in a hardening or limitation of the rights of the convicted person is unlawful … ». No law can be applied retroactively to the detriment of a person. No one may be deprived of liberty or of property, possessions or rights, except by proceedings before the courts previously established, in which the essential formalities of the procedure have been completed, and in accordance with the laws promulgated prior to the act. In the processes of the criminal order. Hence the various guarantees of the judicial system in the field of criminal law. In a broad sense, the principle of reservation of rights is the set of provisions whose regulation concerns only parliaments and which must be defined in the form of a law. In fact, this is one of the principles on which administrative law is based, namely that applicable to public administration. On the other hand, the administration can dictate its own rules, always within the limits established by law.
In turn, it legitimizes the actions of the state by subjecting it to the same laws as citizenship.