Public Law


Public law is the branch of law whose main purpose is to regulate and monitor the different links that are established between individuals and private institutions that are related to public power , as long as these sectors are protected by the public powers of a legitimate nature and following the statutes of the law . It is a group of norms whose function is to regulate all those activities carried out by the Statewith respect to their sovereign functions and their relations with the inhabitants. In it, it is the State that has privilege over other people or institutions.

What is public law?

Public law is the legal order that allows adequate relations of subordination , cooperation and management between the State and the people who inhabit a given place, regulating the exercise of the sovereign functions of public power.

  • What is public law?
  • Characteristics
  • Legal nature
  • Background
  • Story
  • Branches
  • Sources or principles of public law
  • Purposes
  • Importance of public law
  • Examples

What is public law?

Public law consists of developing a series or group of general conditions based on freedom and security , which allows the inhabitants or groups that make up a society to acquire a series of interests in particular through the State . It regulates the correct exercise of the powers that make up the State, always seeking to seek different collective or common interests .



Its main characteristics are the following:

  • It is one of the most specific branches of law because it focuses on the relationships between specific and particular groups within a society.
  • It is in charge of the issues that may affect a person within the public sphere .
  • It involves links between a person and a state entity.
  • Heteronomy and mandatory rules predominate .
  • It is in contrast to the private law .

Legal nature

The Public Law and its legal nature can be defined as a set of rules governing the legal form of organization and proper functioning of the state and relations between citizens and the state. They are the legal norms on the organization of the state apparatus itself, and all its functions


The law began in Rome, and was based on the phrase ” Publicum ius est quod ad statum rei romanae spectat “, which means that public law is one that deals with the government of the Romans, and was divided into three different types:

  • Sacred : it was the cult that the inhabitants gave to the gods, to their rites and sacrifices.
  • Priests : referred to their organization, functions and prerogatives.
  • Magistratus : regulated the number, nature and powers; the competition and organization of the town and senate assemblies.

Public law basically referred to the government , the organization and functions of the State , and the relationships that existed with individuals and other States. The rules that were part of this right could not be modified by agreement between individuals. The organs belonging to the state were those that were in charge of expressing the will of the people , at that time, the Roman people.


Public law originated in Rome and its development has been classified into different periods, ranging from the founding of the Roman Empire to the establishment of the Justinian Empire . In each of these periods we find particular characteristics that distinguish them. There were four phases within the history of public law and they are:

  • Archaic Roman law : It goes from the founding of Rome to the promulgation of the laws of the XII Tables.
  • Pre-classic Roman law : From the promulgation of the Laws of the XII tables until the end of the Republic.
  • Classic Roman law : From the end of the Republic to the empire of Alexander Severus.
  • Postclassic Roman Law : From Alexander Severus to Justinian.
  • Justinian Roman law : What the Justinian Empire lasted.


The branches of public law are:

  • Constitutional right
  • Civil Procedural Law
  • Criminal Procedural Law
  • Administrative law
  • Tax Law
  • Registry and Notary Law
  • Public International Law
  • Ecclesiastical Law

Sources or principles of public law

These sources depend on each State , however, there are sources that are applicable everywhere to maintain the legal order and these are:

  • Principle of legality
  • Separation of duties
  • Limiting principles of criminal law
  • Due process
  • Ignorantia iuris non excusat


Its purpose is to maintain order and regulate the different links between individuals and the State, regulating the subordination and ordering relationships that exist between the States and the people of a society.

Importance of public law

Public law is important because of the unequal relationship between the government and the inhabitants . The government is the only body that can make decisions about people’s rights and they must act within the law. Thanks to public law, a person can request a judicial review if they are not satisfied with the decision of an authorized body. It is important because it defends people when there are unbalanced relationships between the individual and the State , or the bodies that represent it.


Some examples observed daily in our society involving public law are:

  • The Financial or Tax Law that is responsible for regulating the different taxes, their requirements, application and penalties.
  • The Municipal Law or public bodies , which seeks autonomy, organization and finances of a given municipality .
  • Labor Law , whose objective is the worker, their rights and duties, labor contracts, their conditions, validity, collective agreements, labor sanctions, vacations, etc.
  • Public International Law whose objective is the action of states and other international entities and their regulation.

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