Resolving Conflicts: International Treaties vs. National Legislation

Conflict Between Treaties and Domestic Law

What happens internally if there is a conflict between a duly incorporated international treaty and a contrary national law? Which ultimately prevails?

Distinguishing Two Situations of Conflict

We must distinguish two primary situations regarding the timing of enactment:

1. The Treaty is Later than the Law: In this case, it is generally recognized that the treaty takes precedence. Since the treaty often has the same force as a law, the principle of lex posterior derogat priori (a later law repeals an earlier one) applies, especially since treaties often contain special rules that apply preferentially.
2. The Law is Later than the Treaty: In this scenario, efforts must be made to avoid conflict. The national law should be given the most favorable interpretation possible that reconciles it with the treaty. This is based on the presumption that the legislature did not intend to violate the state's treaty obligations.

However, if the terms of the subsequent national law are categorical and unequivocally against the treaty, the fundamental question remains: Which ultimately prevails—the law or the treaty?

Constitutional Approaches to Treaty Supremacy

The definitive answer depends on the respective country's constitutional system. Generally, systems fall into two categories regarding the internal hierarchy of treaties:

• Treaties Equal to Laws (Lex Posterior Rule)

  In some systems, treaties have the same internal force and authority as ordinary laws. Consequently, a later national law can prevail over an earlier treaty. This principle is adopted by the jurisprudence of countries such as the USA, Switzerland, and Denmark.

• Treaties Superior to Laws (Constitutional Supremacy)

  In other constitutional systems, the treaty takes precedence over domestic laws and must therefore prevail. Examples include:

  • France: The French Constitution provides that treaties or agreements duly ratified or approved have, since their publication, a higher authority than the laws, conditional upon each agreement or treaty's implementation by the other party.
  • The Netherlands: The Constitution states that laws governing within the kingdom shall not apply if their application is found to be incompatible with the mandatory rules contained in conventions held either before or after the enactment of such provisions.
  • Chile: Article 5, paragraph 2, of the Chilean Constitution prescribes that "it is the duty of the organs of state to respect and ESSENTIALLY promote the rights emanating from human nature guaranteed by this Constitution and by international treaties ratified by Chile that are in force."

Implementation of International Law at the Global Level

At the international level, the superiority of international law over domestic law is accepted without discussion. A state cannot invoke the provisions of its domestic law (or the deficiency or lack thereof) to justify the breach of a duty imposed upon it by international law.

In other words, a state cannot claim that:

• Its legislature refused to pass a law needed to ensure compliance with international obligations.
• Its executive branch enacted a law that contravenes international law.
• It can hide behind its political constitution, or the independence and separation of state powers, to avoid international responsibility.

This principle ensures the effectiveness and uniformity of international obligations regardless of internal legal structures.