National law refers to the body of laws that govern a particular nation or state. It includes both judge-enforced laws and non-judiciate-enforced laws.

National legal systems are a complex and variable combination of local laws and international law, which often overlaps in scope. For example, a state may incorporate international legal obligations into its domestic law by specific “transformational” devices (such as general transformation or special transformation).

A country may also have national jurisdiction over supranational tribunals. These can include courts and bodies such as the European Court of Human Rights or the International Criminal Court.

The relationship between national and international law is a difficult issue to address. It is often a question of determining which rules are most relevant in a given situation and, therefore, have priority.

It is generally believed that there are two basic approaches to this problem: monist and dualist. The UK, for example, uses a dualist approach and The Netherlands, for example, takes a mitigated monist perspective.

Both approaches have important ramifications for the interpretation of treaties. On the one hand, monist and dualist national law systems deny that a treaty can become binding in the national legal system until it is transposed into national law. On the other hand, a mitigated monist legal system requires that all binding international instruments are transposed into national law before they have direct effect in the legal order of the nation.

The question of which legal system is appropriate in a given situation is an important one for lawyers. It can be a difficult decision to make, but it is essential in terms of establishing legal certainty.