When countries come together to sign treaties, many might assume these agreements only exist at the international level, far from the affairs of daily governance. However, the impact of these treaties can extend directly into the laws within each country that signs them.
These agreements may start as global decisions, but their effects are often felt in the courts, parliaments, and legal systems of individual nations. Treaties signed at global conferences or negotiated through regional blocs can quietly shape the way laws are interpreted and enforced within each member state.
For some countries, a treaty becomes binding on local institutions the moment it’s ratified. Others treat such agreements as guides unless they’ve been domesticated through proper legislative processes.
What’s signed abroad can reshape laws at home (Photo: Shutterstock)International promises meet national procedures halfway
The way international commitments become part of internal legal operations depends largely on the country’s legal tradition—whether it’s monist or dualist. This distinction plays a key role in determining whether a treaty becomes law immediately or only after local approval.
Let’s now look at how these legal systems absorb treaties, how courts use them, and what happens when international promises conflict with national laws.
The Difference Between Monist and Dualist Approaches
Countries that follow a monist structure treat treaties as part of their legal order once ratified, without needing a new law passed by the legislature. In such places, once a treaty is signed and approved by the relevant authority, it can be applied by judges and government officials. For instance, in nations like the Netherlands or France, courts can refer to treaty provisions directly, provided those treaties have been properly approved.
On the other hand, countries with a dualist system, such as Nigeria or the United Kingdom, do not automatically give treaties legal weight. Before such international agreements can have any influence on local courts or administrative decisions, they must be passed into law by the national assembly or parliament. This means that even if a country has agreed to an international treaty, the treaty has no real effect unless lawmakers have adopted it as part of the legal code.
This difference in approach can sometimes create confusion, especially when treaties contain provisions that contradict existing laws. In dualist states, the local legislation takes priority unless the treaty is domesticated. Monist states, however, may find themselves in situations where treaties override conflicting national laws once they become valid.
Influence on Constitutional Interpretation
Even when a treaty has not yet been domesticated, courts in some countries still take notice of its contents. Nigerian judges, for example, may consider treaty provisions when trying to understand human rights guarantees in the Constitution. While such treaties may not carry the force of law, they can provide guidance on how local laws should be read, especially where those laws are ambiguous or open to different meanings.
In certain legal disputes, international treaties act as persuasive authorities. Judges might refer to them to understand international standards or to support the interpretation of local rights. This does not mean the treaty has become law, but it does reflect the growing importance of international norms in shaping how courts reason through difficult cases.
Domestication and Its Legal Importance
For countries that require domestication, the process of converting a treaty into domestic law involves careful legislative activity. In Nigeria, for example, once the President signs a treaty, it is submitted to the National Assembly for ratification. If lawmakers approve, the treaty becomes law and can be cited in courts and applied by regulatory bodies.
This step is important because it allows elected representatives to review the treaty’s content before it becomes part of the national legal framework. Without this review, the treaty may contain provisions that clash with cultural values, established practices, or constitutional provisions.
When domestication does not occur, treaties remain inactive within the country. This creates a gap between the country’s international obligations and what happens within its borders. In some cases, this gap can lead to accusations of non-compliance at the global level.
When Domestic Laws and Treaties Disagree
One common issue is the conflict between domestic laws and international agreements. If a treaty says one thing and a national law says something else, what happens next depends on the legal system. In monist states, treaties may take precedence, meaning the domestic law becomes invalid to the extent of the conflict. In dualist states like Nigeria, the local law remains in force unless lawmakers change it.
Such clashes are particularly common in areas like trade, environmental protection, and human rights. A country might agree to reduce tariffs under a trade deal, but local law might still maintain import restrictions. If the treaty is not domesticated, customs officials will enforce the local law. This situation can lead to complaints from trading partners or disputes at international tribunals.
In some situations, local courts attempt to harmonise the conflict by interpreting the local law in a way that aligns with the treaty’s goals. However, this can only go so far. Where clear contradictions exist, the solution often lies with the lawmakers, who must decide whether to amend the existing law or withdraw from the treaty altogether.
Role of Judiciary in Treaty Enforcement
Judges play a vital role in determining how treaties interact with domestic legal systems. In countries with strong constitutional courts, such as South Africa or India, judges often refer to international human rights treaties when deciding cases about individual freedoms. These references serve as tools for interpreting constitutional rights in a broader, more contemporary manner.
One treaty two outcomes depending on the legal system (Photo: Alamy)However, in countries where judicial independence is under pressure, courts may be hesitant to rely too heavily on international law, especially where such treaties challenge existing political or religious values. In such settings, the ability of treaties to shape legal outcomes becomes limited, even if the country has ratified the agreement.
Treaties and Legal Reforms
International treaties can also prompt legal reform by encouraging countries to adopt new policies or change outdated laws. Agreements on anti-corruption, climate change, and gender equality often come with suggestions or obligations that push governments to amend existing legal codes. These changes may take years, but the treaty can serve as a reference point for activists, lawyers, and legislators pushing for reform.
For example, the Convention on the Rights of the Child has influenced several African countries to raise the legal age of marriage. Although the treaty itself may not have the force of law in every country, it has become part of the conversation around what is considered acceptable by global standards.
In this way, treaties contribute to a gradual adjustment of domestic legal norms. The changes may be slow, but they reflect the growing interaction between international agreements and national legal practice.
The connection between international treaties and domestic laws is shaped by each country’s legal tradition, political will, and judicial independence. While some nations automatically give treaties a place in their law books, others demand a legislative process before such agreements can be enforced. Even without legal status, treaties can influence judicial thinking, inspire reform, and highlight areas where local laws may fall behind global expectations.
What matters most is how seriously countries treat their international promises and whether these promises are backed by internal changes. Treaties, on their own, do not fix problems or transform legal systems. It is the response of each nation—through its courts, lawmakers, and public officials—that determines whether those international commitments mean anything within its borders.