International Treaties and National Legal Systems

International Treaties and Domestic Law

Government's Role in Foreign Policy

It is a function of government to conduct foreign policy. The adoption of treaties manifests the government's consent, corresponding to the Head of State (the King). This consent may be countersigned by the President or the Minister of Foreign Affairs.

Categories of Treaties and Approval Processes

The Constitution (Article 93 et seq.) refers to several categories of treaties:

• Treaties Ceding Constitutional Powers: These include treaties that transfer constitutional powers to an international organization, such as the European Union accession treaty. Such treaties, due to their supranational character, require approval by an Organic Law.
• Treaties Requiring Parliamentary Approval: This second type does not require an Organic Law but necessitates approval by the Cortes Generales (General Courts). This category includes treaties of a political or military nature, those affecting the territorial integrity of the state, or those that assume financial obligations for the Public Treasury. A formal authorization from the Cortes is required for consent.
• Treaties Requiring Information to the Cortes Generales: For other treaties, only information to the Cortes Generales is required.

It is crucial that the classification of a treaty is correct, as an incorrect classification could lead to its unconstitutionality. The congressional authorization process can effectively act as a veto.

Publication and Enforcement of Treaties

The final phase for a treaty's entry into force domestically is its publication in the Official State Gazette. Special agreements may also be published in other newsletters, for example, the Official Journal of the European Union.

Ensuring the respect and compliance of treaties rests with the government and parliament. While compliance is binding on all Autonomous Communities, the ultimate guarantee of compliance remains in state hands.

Normative Hierarchy of International Treaties

International treaties possess a double perspective regarding their normative rank: at the international level and at the domestic level.

International Law Perspective

In international law, treaties generally prevail over domestic rules. An example of such a treaty is the Nuclear Non-Proliferation Treaty. While the state bears responsibility for its compliance, treaties are ultimately subject to the Constitution.

Domestic Law Perspective and Constitutional Review

Article 95 of the Constitution addresses the situation where a treaty is deemed contrary to the Constitution, necessitating its reform before ratification.

The Constitutional Court (TC) plays a crucial role in overseeing the constitutionality of treaties. The Government, Congress, and Senate can request a review to determine if a treaty is constitutional.

Treaties approved by Organic Law (as per Article 93) have a specific legal force. They cannot be superseded by a subsequent ordinary law, nor can an ordinary law regulate matters already covered by such a treaty.

Less relevant treaties (those not requiring Organic Law or parliamentary approval) also possess the force of law once properly ratified and published.

It is important not to confuse treaties with ordinary laws, as treaties cannot be unilaterally changed by domestic legislation. A treaty supersedes internal rules that contradict it, effectively "absorbing" the material it covers, preventing subsequent domestic laws from entering that specific area.

Furthermore, treaties must respect the autonomy statutes of the Autonomous Communities. While a treaty cannot violate the Constitution or the autonomy statutes, it must align with the broader "constitutional bloc" – the set of rules that, along with the Constitution, determine constitutionality.