Public Law – Concept, branches of study and examples


We explain what public law is and the branches of study that comprise it. Also, its difference from private law and examples.

Public Law
Public law, together with private law, makes up the branch of positive law.

What is public law?

It is known as the public right to a part of the legal systems whose norms concern public power and its relations with individuals, organizations and with itself, provided that this is exercised as a representation of the interests of the State.

In other words, it is the branch of positive law that orders subordination and superordination relations between the State (represented by the Public Administration) and individuals, as well as between the different bodies that make up the Public Power.

Together with private law, it makes up the branch of positive law, that is, that which is contained in written legislation (Constitution, Law, etc.) and agreed and accepted by the community in which it governs.

Therefore, public law is also part of the legal system built by societies to govern their own operation, and to which all of them choose to submit.

Public law can vary enormously according to the nation it governs, but in general terms it is governed by two guiding principles:

  • Principle of legality. It establishes that any action of the public powers must necessarily be registered in the current legal order, that is, it must have legal certainty, according to its jurisdiction and nature. That is to say: the State cannot violate the laws.
  • Principle of empire. It establishes that any relationship between the State and individuals is exercised from a situation of inequality in which the former has dominance (imperium) for which it will be exercising a public authority. That is to say: the State is the authority.

Branches of public law

Criminal law
Criminal law is responsible for punishing those who violate the law, among other things.

The branches of public law are usually the following:

  • Constitutional right. That branch that concerns the interpretation of the legal texts of the Constitution and other written ordinances that are fundamental in the construction of the State.
  • Administrative law. That which regulates the public administration and modulates the functioning and relations between the various bodies that make up the State.
  • Public international law. It concerns the relations between the different Nation-States of the planet: their joint plans, their economic agreements and exchanges, their border disputes, etc.
  • Criminal law. It has to do with the punitive capacity of the State, that is, its capacity to punish those who violate the law and to exercise coercion on the citizens among whom it prevails.
  • Procedural law. It regulates the mechanisms and procedures of the State regarding the way in which it exercises its power, guaranteeing the minimum rights and the proportion at all times.
  • Labor law. That branch linked to the legal framework that regulates work to guarantee its dignity, legality and fair remuneration, as well as the rights and duties of workers, employers, unions, etc.
  • Financial law. Regulates public spending processes, to guarantee transparency and good behavior of the State in its use of public funds.
  • Tax law. That which has to do with taxes, tributes and other forms of tax collection, which the State uses to finance itself.
  • Electoral law. It is responsible for regulating the procedures for the succession of power and replacement of rulers at all levels, in any of the public powers.

Difference between public and private law

The difference between public and private law dates from the ancient years of Roman Law, when the need to distinguish between legal matters related to individuals (Private Law) and those that concern the “Res Pública”, that is, the public “thing” of the State (Public Law) was imposed.

Both branches differ, therefore, in their scope of action: when it comes to matters that involve individuals or even the State acting as one of them (commercial operations, inheritance, private property, etc.) we will speak of private law; when it comes to the State and the rules of coexistence and the social pact (public order, public funds, operation of the State, etc.) we will speak of public law.

Examples of public law

The public law examples are simple and abundant:

  • The conviction of a criminal who was captured by the security organs (criminal law) and tried by an appropriate court (procedural law).
  • The interpretation of what is established in the National Constitution (constitutional law) to determine whether or not a presidential election proceeded correctly (electoral law).
  • The revision of international sovereignty treaties to mediate in a third country in conflict (public international law).
  • Defend a worker whose rights have been violated (labor law).