Public international law concerns the structure and conduct of sovereign state

Sovereign state

A sovereign state, or simply, state, is a state with a defined territory on which it exercises internal and external sovereignty, a permanent population, a government, and the capacity to enter into relations with other sovereign states. It is also normally understood to be a state which is neither...

s; analogous entities, such as the Holy See

Legal status of the Holy See

The legal status of the Holy See, both in state practice and according to the writing of modern legal scholars, is that of a full subject of public international law, with rights and duties analogous to those of States....

; and intergovernmental organizations. To a lesser degree, international law also may affect multinational corporation

Multinational corporation

A multi national corporation or enterprise , is a corporation or an enterprise that manages production or delivers services in more than one country. It can also be referred to as an international corporation...

s and individual

Individual

An individual is a person or any specific object or thing in a collection. Individuality is the state or quality of being an individual; a person separate from other persons and possessing his or her own needs, goals, and desires. Being self expressive...

s, an impact increasingly evolving beyond domestic legal interpretation and enforcement. Public international law has increased in use and importance vastly over the twentieth century, due to the increase in global trade

International trade

International trade is the exchange of capital, goods, and services across international borders or territories. In most countries, such trade represents a significant share of gross domestic product...

, environmental deterioration on a worldwide scale, awareness of human rights

Human rights

Human rights are "commonly understood as inalienable fundamental rights to which a person is inherently entitled simply because she or he is a human being." Human rights are thus conceived as universal and egalitarian . These rights may exist as natural rights or as legal rights, in both national...

 violations, rapid and vast increases in international transportation and a boom in global communications.

The field of study combines two main branches: the law of nations (jus gentium

Jus gentium

Ius gentium, Latin for "law of nations", was originally the part of Roman law that the Roman Empire applied to its dealings with foreigners, especially provincial subjects...

) and international agreements and conventions (jus inter gentes

Jus inter gentes

Ius inter gentes, or ius inter gentes, is the body of treaties, U.N. conventions, and other international agreements. Originally a Roman law concept, it later became a major part of public international law. The other major part is jus gentium, the Law of Nations referred to in the United States...

), which have different theoretical foundations and should not be confused.

Public international law should not be confused with "private international law", which is concerned with the resolution of conflict of laws

Conflict of laws

Conflict of laws is a set of procedural rules that determines which legal system and which jurisdiction's applies to a given dispute...

.