International Law

Governments, states and countries make and enforce laws.  International law looks at how states deal with issues matters persons and entities outside of their jurisdiction.

There are two principal aspects of international law. Public international law deals with relationships between states.  It also deals with matters such as international disputes, responsibility to aliens, state territories and relationships between states.

Private international law deals with matters concerning citizens, individuals and corporates.

Court Jurisdiction

Courts in a state may hear disputes with an international aspect, provided there is some connection with the particular state. The state’s own private international law determines its rules in relation to dealing with foreign matters.

Each state will deal with matters where there is a certain level of connection with the state, such as residence, incorporation or establishment, or the subject matter of the dispute. Courts may act in disputes because of the nationality, resident or territorial basis of the dispute.

Conflicts can arise when more than one state claims power or jurisdiction to deal with the matter.  However, international treaties and court practices minimize the conflicts that arise in practice.  On occasions, courts which may have jurisdiction may defer where the court of another state has a greater connection with the dispute.

International Law

International law between states exists by practice or treaty.  Each country is a party to a large web of treaties setting up institutions or dealing with numerous specific matters.

Treaties are usually binding between two or more states.  Conventions are binding between state parties, sponsored by an international organization such as the U.N.

Some international laws between states exist by long custom.  There are certain norms or general principles common to the legal systems of most countries.  These principles may be recognised by international organisations.  States generally regard themselves as bound by these basic principles.

In the Middle Ages, merchant law grew by way of the customs of merchants in business matters.  This led to internationally commercially accepted rules that transcended national boundaries.

Monism and Dualism

In some countries, such as the United States, international treaties apply directly as domestic law.  In other countries such as the United Kingdom and Ireland, international treaties do not take effect unless transposed into law.

Generally, governments enter into treaties.  In some states, they must also be ratified by parliament.

In the United States, for example, the President enters treaties, but the Senate ratifies them.  In Ireland, the government enters treaties, but the Oireachtas ratifies them.  Only the legislature can make them domestic law.

Legal Systems

There are over 200 nations in the world with different sets of legal systems.  Some legal systems fall into a number of broad classifications.

There are sub-families within each classification.  Many systems fall in into either a classification or have elements of more than one.


Civil law systems are heavily influenced by the compilation and codification of Roman law in the sixth century.  The importance of this system is that it became preserved in writing.

Interest was revived in the codes after the Renaissance, and they were systematically analyzed by annotators and commentators.  This led to the creation of a civil law based on Roman law, canon law and the writings of annotators and commentators.

Civil Codes

Two national codes, the French Civil Code and German Civil Code, became the model for a large number of other civil codes throughout continental Europe and beyond.

The French Civil Code of 1804 preserved much of the Jus Commune French law ordinances and customary law.  It largely involved rationalising and modernizing previous laws in simple terms that could be understood by the public. The code could not foresee every eventuality and accordingly set out general rules.

The German Civil Code was published in 1896.  It was based on studies of earlier codes and attempts to set out underlying principles.  It is more highly structured and technically precise than the French Codes.  The French Code is aimed at the public, whereas the German Code is aimed more at trained lawyers.

A feature of German and French systems is the development of a distinct public law.  Civil law deals largely with issues between private individuals.  Public law deals with issues between the state / administrative agencies and individuals.  Special administrative courts are a feature of continental legal systems.

Common Law

The Common Law System is derived from English unwritten law.  This law was consolidated in law reports.  Blackstone\’s treatises, dating from the 17th Century, were influential in consolidating and restating Anglo Common Law.

It was exported and used widely throughout the United States.  The Irish system is largely based on common law and shares a common heritage.

Common law has extended to the English-speaking world, including Australia, Canada, India, New Zealand, the United Kingdom, United States.

Islamic Law

The Islamic legal system recognises Sharia law.  It is made up of traditional Koran teachings and practices, writings of scholars derived by analogy from the principles and the consensus of the legal community.  The code is primarily moral, dealing with ethics more than commercial or business relationships.


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