Principle of legality


One of the principles considered the most important within the area of criminal law today is the so-called principle of legality . Its essence that tells us that there can be no type of crime or penalty without the existence of a prior law or “nullum criminality nulla poena sine previa lege” is the basis of the legal system of every nation. It is also a fundamental principle with respect to public power , which must be carried out depending on the law and not according to the will of the people .

What is the principle of legality?

The rule of law is a principle critical of states that says that all public power must always adhere to the laws that are in force and jurisdiction and should never be guided by the will that may have people .

  • What does it consist of
  • Characteristics
  • Principle of constitutional legality
  • Administrative legality principle
  • Principle of tax legality
  • Principle of criminal procedural legality
  • Consequences
  • Source
  • Story
  • Principle of legality by country
  • Importance
  • Examples

What does it consist of

The principle of legality is a fundamental public right that consists in the fact that all the exercise of the different powers must be based on the legal norms determined by a competent body and in its jurisdiction . It consists of ensuring legal security and is a parameter to be able to speak of a rule of law since it is on it that the different legal norms are based.


The doctrine says that the principle of legality is the right that must accompany any act carried out by the bodies that are in charge of exercising political power in a state, in other words it is a principle that dictates that all activities of the State must to be in accordance with the law of the State . It is a system in which all the administrative acts that are carried out are subject to legality , which in turn forms the measure of the legality of the acts.


The main characteristics of the principle of legality are the following:

  • Submit to the public authorities with respect to their actions in legal security .
  • It is considered as a golden rule in the area of public law .
  • It is the basis for a state to be considered as a rule of law .
  • It establishes that a ruler cannot act against the Political Constitution, so all its measures must be subject to the law.
  • It is protected through the division of powers .
  • Criminal law is based on the principle of legality .
  • It gives the legislature a little more powers in some areas related to fundamental rights.
  • It promotes the separation of powers in governments.
  • It is in charge of informing the legal system of a country through a constitutional text .
  • It also plays an important role within the field of administration and the criminal field . 

Principle of constitutional legality

In democracies, the principle of constitutional legality is protected through the division of powers . By means of a legal order, the power that must interpret the laws is prevented from being the same that proposes or executes them . If this principle did not exist, governments could create laws of any kind. Thanks to the principle, it is monitored that the laws are complied with within a  principle of legality .

Administrative legality principle

This principle refers to the foundation by virtue of which acts of an administrative nature are related to the contracting , management and disposition of the goods and services that the public sector owns, and how they must be subject to the laws and administrative sanctions. that can only be imposed when they have been provided for by means of an express rule.

It is linked to a guarantee linked to the criminal principle that says that no person can be punished for acts or omissions that were not foreseen as a crime , a fault or infractions in the laws that already existed. It also requires the presence of a legal norm that typifies the conduct that is sought to be punished and that in turn establishes the sanction that must be applied to the people who engage in this conduct . It depends on the principle of criminal law .

Principle of tax legality

The principle of tax legality is a requirement to create a tribute , it is not only the result of the demand for popular representation , but it implies the need to guarantee security to citizens against their obligations , and also represents the importance of a design with meaning in the fiscal policy of a State. It is in charge of defining the tribute to indicate the elements and the fiscal obligation and to guarantee popular representation, providing certainty to the taxpayers about their different fiscal obligations.

Principle of criminal procedural legality

It is the main limit to the exercise of ius puniendi by the State, since the public powers are subject to the law in all its dimensions, so the criminal process is carried out with full guarantees . It must ensure the effectiveness of guarantees and basic principles. It is the relationship of the State through organs that have already been designated in the face of a hypothesis of the commission of a certain crime that demands an investigation or a trial and, if applicable, a punishment of the crime that could have been proven.


The consequences of the principle of legality are three:

  • Exclusivity : only in criminal law are descriptions of crimes and sanctions that can be applied to offenders located. Criminal law is the only source of Criminal Law.
  • Exclusion, elimination and prescription of the criminal field analogy : it is eliminated because according to the legalistic principle , for an act to be considered a criminal act it must be identical to one of the foreseen acts and not simply similar.
  • Irretroactivity : it cannot be applied to acts prior to its entry into force, unless it is in favor of the inmate.


The principle of legality has its origin in the 18th century and was born as a reaction against arbitrariness , against the abuse of power and against the political insecurity that existed at the time. Some people mention that it originated in clause number 39 of the Magna Carta .


It is considered that indications of the beginning were given from the beginning of Roman law , although its history is fully born in the Magna Carta pronounced in the year 1215, when King Juan Sin Tierra made a series of concessions to the nobles of England. Later this principle was also taken up by the Declaration of the Rights of Man and the Citizen in France and by the Constitution of the United States in 1787. It also became part of the Argentine Constitution and as time passed, it was adopted by all states that have contemporary legislation , with the exception of totalitarian states that rely on force to achieve their political goals.

Principle of legality by country


In Mexican law, mainly in the administrative field , this principle is deduced jointly from the article that says that no person can be deprived of life , liberty , property , possessions or rights if it is not through trials before the courts that have been previously established for this mission.


It is contemplated in article 18 of the National Constitution of the country and it is a principle that establishes that no person can be tried or punished for a crime, without a law that has contemplated the crime as such. It is considered as the main pillar of the suprasystem of guarantees since it establishes the limits that the punitive power of the State has.


In the Spanish Constitution we can find this principle within article 93 where it tells us that no person can be sentenced for their actions or omissions that when they occur do not constitute a crime , offense or an administrative offense depending on the legislation that exists at the time .


In Colombia it has a double condition because on the one hand it is the guiding principle of the exercise of power and it is also the guiding principle of sanctioning law . As a guiding principle, it is understood that there is no power , function or act that public servants can carry out that is not prescribed , defined or established clearly and precisely in the law . It is a principle that requires all State officials to be subject to the legal system established by the Constitution.


With the passage of time, the principle of legality has become more important since everything in addition to making the law work properly, provides the ability to create taxes and at the same time imposes limits on the power of imposition that the State has. It also makes the law work by forcing all the agencies and powers of the State to be based on a previous law.


As examples of the principle of legality we can mention the creation of taxes in a fair manner and the vigilance of the State so that it correctly fulfills its functions .

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