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Public law is that part of law which governs relationships between individuals and the government, and those relationships between individuals which are of direct concern to society. Public law comprises constitutional law, administrative law, tax law and criminal law, as well as all procedural law. In public law, mandatory rules prevail. Laws concerning relationships between individuals belong to private law.
The relationships public law governs are asymmetric and unequal – government bodies (central or local) can make decisions about the rights of individuals. However, as a consequence of the rule of law doctrine, authorities may only act within the law (secundum et intra legem). The government must obey the law. For example, a citizen unhappy with a decision of an administrative authority can ask a court for judicial review.
Rights, too, can be divided into private rights and public rights. A paragon of a public right is the right to welfare benefits – only a natural person can claim such payments, and they are awarded through an administrative decision out of the government budget.
The distinction between public law and private law dates back to Roman law. It has been picked up in the countries of civil law tradition at the beginning of the nineteenth century, but since then spread to common law countries, too.
The borderline between public law and private law is not always clear in particular cases, giving rise to attempts of theoretical understanding of its basis.
Public law in civil law and common law jurisdictions
Rule of law, the idea that the administration of the state should be controlled by a set of laws, originated in Greek Antiquity and was revitalized by modern philosophers in France (Rousseau), Germany (Kant) and Austria in the 18th century. It is related to the strong position of the central government in the era of enlightened absolutism, and was inspired by the French Revolution and enlightenment. It developed hand in hand with the creation of civil codes and criminal codes.
Areas of public law
Secondly, it sets out the form of government – how its different branches work, how they are elected or appointed, and the division of powers and responsibilities between them. Traditionally, the basic elements of government are the executive, the legislature and the judiciary.
And thirdly, in describing what are the basic human rights, which must be protected for every person, and what further civil and political rights citizens have, it sets the fundamental borders to what any government must and must not do.
In most jurisdictions, constitutional law is enshrined in a written document, the Constitution, sometimes together with amendments or other constitutional laws. In some countries, however, such a supreme entrenched written document does not exist for historical and political reasons – the Constitution of the United Kingdom is an unwritten one.
Administrative law refers to the body of law which regulates bureaucratic managerial procedures and defines the powers of administrative agencies. These laws are enforced by the executive branch of a government rather than the judicial or legislative branches (if they are different in that particular jurisdiction). This body of law regulates international trade, manufacturing, pollution, taxation, and the like. This is sometimes seen as a subcategory of civil law and sometimes seen as public law as it deals with regulation and public institutions
Theoretical distinction between private and public law
In German-language legal literature, there is an extensive discussion on the precise nature of the distinction between public law and private law. Several theories have evolved, which are neither exhaustive, nor are they mutually exclusive or separate from each other.
The interest theory has been developed by the Roman jurist Ulpian: "Publicum ius est, quod ad statum rei Romanae spectat, privatum quod ad singulorum utilitatem. (Public law is that, which concerns Roman state, private law is concerned with the interests of citizens.) The weak point of this theory is that many issues of private law also affect the public interest. Also, what exactly is this public interest?
The subjection theory focuses on explaining the distinction by emphasizing the subordination of private persons to the state. Public law is supposed to govern this relationship, whereas private law is considered to govern relationships where the parties involved meet on a level playing field. This theory fails in areas commonly considered private law which also imply subordination, such as employment law. Also, the modern state knows relationships in which it appears as equal to a person.
The subject theory is concerned with the position of the subject of law in the legal relationship in question. If it finds itself in a particular situation as a public person (due to membership in some public body, such as a state or a municipality), public law applies, otherwise it is private law.
A combination of the subjection theory and the subject theory arguably provides a workable distinction. Under this approach, a field of law is considered public law where one actor is a public authority endowed with the power to act unilaterally (imperium) and this actor uses that imperium in the particular relationship. In other words, all depends whether the public authority is acting as a public or a private entity, say when ordering office supplies. This latest theory considers public law to be a special instance.
There are areas of law, which do not seem to fit into either public or private law, such as employment law – parts of it look like private law (the employment contract), other parts like public law (the activities of an employment inspectorate when investigating workplace safety).
The distinction between public and private law might seem to be a purely academic debate, but it also affects legal practice. It has bearing on the delineation between competences of different courts and administrative bodies. Under the Austrian constitution, for example, private law is among the exclusive competences of federal legislation, whereas public law is partly a matter of state legislation.