Tacit Agreement International Law

Tacit Agreement in International Law: Understanding the Concept

International law is a complex and ever-evolving field that governs the relationship between nations and international organizations. One of the key concepts of international law is the tacit agreement, which refers to an agreement that is reached without being explicitly stated. This article will explore the concept of tacit agreement in international law, its legal implications, and how it is used in practice.

What is Tacit Agreement?

Tacit agreement is a legal concept that refers to an agreement that is reached without being explicitly stated. In international law, tacit agreement occurs when the actions or behaviors of parties are consistent with a specific course of conduct or practice, which is then interpreted as an implicit agreement.

For instance, when two countries engage in trade relations for a prolonged period without explicitly signing a formal agreement, they may be considered to have reached a tacit agreement. Similarly, if a country consistently refrains from taking action against a neighbor`s territorial claim, it may be interpreted as tacit acceptance of that claim.

Legal Implications of Tacit Agreement

Tacit agreement has legal implications in international law. It is considered a binding agreement, just like a formal agreement, and can be used as evidence in a court of law. The International Court of Justice (ICJ) has recognized and enforced tacit agreements in several cases, such as the Gabčíkovo-Nagymaros case, where the court found that a tacit agreement existed between Slovakia and Hungary concerning their shared Danube River.

Furthermore, a party that claims to have reached a tacit agreement must provide sufficient evidence to support that claim. The evidence must demonstrate that there was a clear and consistent pattern of conduct or practice that led the party to conclude that an agreement existed.

The Use of Tacit Agreement in Practice

Tacit agreement is a useful concept in international law because it allows parties to reach an agreement without the need for a formal or written agreement. It facilitates the smooth functioning of international relations, particularly when there are cultural or linguistic differences that can make it challenging to draft a formal agreement.

However, the use of tacit agreement can also create uncertainty and ambiguity, as parties may have different interpretations of what constitutes a tacit agreement. Therefore, it is essential to clarify the scope and terms of any tacit agreement to avoid misunderstandings and disputes.


Tacit agreement is a key concept in international law, and it is essential to understand its legal implications and use in practice. It provides a flexible and efficient way for parties to reach an agreement without the need for a formal agreement, but it also requires clear evidence and mutual understanding to be effective. As international relations continue to evolve, the concept of tacit agreement will remain relevant and critical for resolving disputes and promoting cooperation between nations and international organizations.