The Competence to Conclude Treaties in International Law and the Invalidity of Treaties within the Scope of Article 46 of the Vienna Convention on the Law of Treaties
Bilge Erson AsarThe regulations governing the domestic procedures that states are to follow in their processes regarding the conclusion of a treaty represent one of the limited areas where international law intersects with domestic law. Nonetheless, the regulations in this area include various procedures. The power to conclude treaties, traditionally vested in the executive, has become a practice shared with the legislature in line with democratization processes. Constitutional courts or judicial bodies with similar powers may be able to be involved in these processes in some states. Other states even have treatyconcluding procedures that require a referendum. If a state becomes a party to an international treaty in violation these rules of domestic law, it may invoke the treaty’s invalidity under Article 46 of the 1969 Vienna Convention on the Law of Treaties (VCLT). While this provision may seem to challenge both internationalism and constitutionalism, its practical application proves to be extremely difficult and rare. Both the complexity of states’ rules on treaty-making and their diverse nature further complicates the matter to the extent that a general categorization becomes challenging. The study delves into the development, scope, and limitations of the relevant provision in VCLT and analyzes why this ground of invalidity, which was one of the most controversial issues in the preparatory work of the VCLT, is highly exceptional and unlikely to succeed if invoked. In addition, this study addresses the applicability of this provision to the rules on withdrawal from treaties that are currently under discussion in academia.
Uluslararası Hukukta Andlaşma Akdetme Yetkisi ve Viyana Andlaşmalar Hukuku Sözleşmesi Madde 46 Kapsamında Andlaşmaların Geçersizliği
Bilge Erson AsarDevletlerin bir andlaşma ile bağlanma süreçlerinde iç hukuklarında uygulanacak usule ilişkin düzenlemeleri, uluslararası hukuk ile iç hukukun kesiştiği sınırlı alanlardan biri olarak karşımıza çıkmaktadır. Bununla birlikte devletlerin bu alandaki düzenlemelerinin çeşitli usulleri içerdiği gözlenmektedir. Geleneksel olarak yürütmenin elinde olan andlaşma akdetme yetkisinin demokratikleşme süreçleriyle birlikte yasama ile paylaşılan bir uygulama halini aldığı görülmektedir. Kimi devletlerde bu süreçlere anayasa mahkemeleri veya benzer yetkiyle donatılmış yargı organlarının da dahil olması mümkün olabilir. Hatta halk oylamasından geçmesi öngörülen andlaşma akdetme usulleri de mevcuttur. İç hukukta öngörülen bu kuralların ihlal edilmesi yoluyla bir uluslararası andlaşmaya taraf olan devlet, andlaşmanın geçersizliğini 1969 Viyana Andlaşmalar Hukuku Sözleşmesi’nin (VAHS) 46. maddesine dayanarak ileri sürebilir. Uluslararasıcılık ile anayasalcılığı bağdaştırıcı bir çözüm sunar gibi gözüken bu hüküm, gerçekte son derece zor ve istisnaî bir uygulamaya sahiptir. Gerek devletlerin andlaşma akdetme konusundaki kurallarının karmaşık olması gerekse genel bir sınıflandırmayı zorlaştıracak kadar çeşitli olması, konuyu daha da çetrefilli hale getirmektedir. Bu çalışma, ilgili hükmün hazırlık çalışmaları, kapsamı ve sınırlarını ayrıntılı bir biçimde incelemektedir. Çalışmada ayrıca, VAHS’nin hazırlık çalışmalarında da en tartışmalı konulardan biri olan bu geçersizlik gerekçesinin neden son derece istisnaî ve ileri sürüldüğünde başarı şansının zayıf olduğu değerlendirilmiştir. Bunların yanında, bu hükmün şu anda akademik çevrelerde tartışılmakta olan andlaşmalardan çekilmeye ilişkin kurallara benzer şekilde uygulanabilirliği de ele alınmıştır.
The primary responsibility of ensuring adherence to the rules governing the treatymaking process lies with the state. As such, states must exercise caution and diligence in transactions that create international obligations. During the treaty-making process, a state may employ diverse methods determined by its own legal system, involving various branches of government. If these methods are not properly followed, a treaty may be concluded in violation of domestic law, creating the possibility of a conflict between domestic and international legal norms. Such a conflict may lead to disputes over the valid implementation and enforcement of the treaty.
In certain cases, a conflict may arise between the legislative and executive branches when the executive expresses its consent to be bound by a treaty without obtaining the approval of the legislature, in violation of the state’s domestic law. This not only disrupts constitutional and democratic processes but also undermines the effectiveness and security of international treaties. In such a scenario, the only means of invoking the invalidity of a treaty, which is in principle presumed to be valid, is Article 46 of the VCLT. This article sets out the grounds for invalidity based on a breach of the competence to conclude treaties. However, Article 46 of the VCLT should be noted for its highly exceptional nature.
To invoke invalidity under Article 46 of the VCLT, the state party wishing to do so must base its claim on a constitutional or equivalent provision. However, this alone may be insufficient. The success of such a claim may depend on whether another state party can clearly identify the violation of such a fundamental rule through normal practice and objective assessment while acting in good faith. Given the diversity and complexity of domestic legal systems in different states, the ability of another state party to identify such violations is further compromised. Moreover, if a state’s domestic law classifies treaty ratification procedures into different categories, such as exclusive executive ratification, joint legislative and executive ratification, or exclusive legislative ratification, a third state’s ability to definitively determine the category to which a particular treaty belongs may prove difficult. Such a determination may even require an assessment of the content and nature of matters falling within the exclusive competence of the invoking state, which would violate the principle of non-interference in internal affairs.
The executive’s ratification of treaties, without involving the parliament which symbolizes the people’s will in the ratification process and in violation of domestic treaty-making rules, could imply that executive branch may alter laws if treaties are deemed equivalent to or superior to domestic legislation. This has the potential for undesirable consequences, especially concerning fundamental rights and freedoms. In fact, a treaty concluded in violation of domestic law will persist in the international arena without a successful claim of invalidity; however, the invoking state may not recognize the treaty as valid under its domestic law due to its failure to be duly entered into force. Therefore, the executive’s action, considered a usurpation of authority under domestic law, might be deemed valid under international law. This situation presents two options: first, the parliament may come under pressure to ratify or approve the treaty to prevent the state from facing difficulties in the international arena; second, the state may choose to violate international obligations by taking no such action.
The most rational solution for a state to avoid such a conflict is to empower the constitutional court (or an equivalent judicial body) to decide on constitutionality or compliance with domestic law of international treaties in preliminary review proceedings. Indeed, this concern has prompted some states to introduce mechanisms for the prospective judicial review of treaties into their domestic legal systems. Despite concerns about the potential lengthening of proceedings in the treaty-making process—a task traditionally within the purview of the executive—due to the inclusion of constitutional review, this step should be regarded as a valuable measure. It aims to prevent potential future claims of invalidity based on violations of internal law in treaty-making and contributes to strengthening the stability and security of treaties.
Considering the seeming unlikelihood of the application of Article 46 of the VCLT to treaty withdrawals, national legal systems are confronted with the urgent task of devising a mechanism to strike a balance in this context, given the absence of any readily available remedy in the field of international law. One potential option under international law might be to revoke the notice of withdrawal in accordance with Article 68 of the VCLT. However, this solution is not definitive, as it must be implemented before the withdrawal becomes legally effective. If, after legal effectiveness, the other state parties accept the revocation of the withdrawal notice, the withdrawing state could then resume its status as a party to the treaty without the need for re-accession procedures. It is essential to note that no objective condition exists requiring unanimous consent for revocation; such a practice remains solely at the discretion of the states that are parties to the treaty.
A proactive step toward this goal would be the widespread inclusion of explicit provisions on treaty withdrawal in national constitutions. At the same time, the democratization the power of withdrawal and denunciation, which is originally vested in the executive, should be restructured as a shared power exercised jointly by the legislative and executive branches. Such a multi-pronged approach has the potential to proactively mitigate the legal dilemmas raised by withdrawals, as exemplified by Türkiye’s withdrawal from the Convention on Preventing and Combating Violence against Women and Domestic Violence (Istanbul Convention), which was made solely by a presidential decision. To consider the establishment of a streamlined procedure for facilitating the re-accession of states that have withdrawn from treaties would be beneficial from the perspective of international law, particularly regarding treaties concerning fundamental rights and freedoms.
