Polarisation, Politics and the Constitutional Interpretation of International Law in Guatemala

Fabia Fernandes Carvalho et al

Fabia Fernandes Carvalho is Assistant Professor at São Paulo State University UNESP Monique Cormier is Associate Professor at the Faculty of Law, Monash University
Tomás Daly is Professor at Melbourne Law School, University of Melbourne
Mateo Merchán Duque is a JSD Candidate at the School of Law, New York University
Anna Dziedzic is an Honorary Senior Fellow, Melbourne Law School, University of Melbourne
Violeta Moreno-Lax is a Professor at the Hertie School, University of Governance in Berlin
Elizabeth Shergold is Senior Lecturer in the Faculty of Law, Monash University

Constitutional Courts are increasingly required to interpret and apply international law. International law has expanded into many areas of public life, interacting with domestic laws and raising questions about which laws apply and what to do in the case of inconsistency. Constitutional review of executive action, including in relation to foreign policy, also brings international law before constitutional courts.

This is also a time of political polarisation, in which international arrangements are being challenged and democratic institutions of government are being eroded in many parts of the world.

These legal and political trends converge in a politically charged case currently before the Constitutional Court of Guatemala. The case concerns the decision to withdraw a reservation made by Guatemala when it ratified the Vienna Convention on the Law of Treaties.

In this post, an international group of comparative constitutional law and international law scholars examine the issues this case raises for the interface of constitutional and international law. While we discussed these issues with Guatemalan legal experts, we do not identify them to protect them from the threat of ‘lawfare’ – the targeted abuse of legal proceedings against political opponents – in their home country.

After outlining the facts of the case and the political context, we identify three areas of interaction between international and constitutional law: legal interpretation, the responsibility and oversight of foreign affairs, and the available remedies. We demonstrate how the Constitutional Court’s approach deviates substantially from orthodox interpretations of international law, with significant consequences for constitutional law in Guatemala and Guatemala’s international reputation. 

The reservation to Article 27 of the Vienna Convention on the Law of Treaties and its withdrawal

Guatemala was one of the original signatories to the Vienna Convention on the Law of Treaties in 1969. When it ratified the Convention in July 1997, Guatemala made a reservation to Article 27.

Article 27 provides that ‘a party may not invoke the provisions of its internal law as justification for its failure to perform a treaty’. Guatemala’s reservation sought to limit the ‘internal law’ referred to in Article 27 to ‘the provisions of the secondary legislation of Guatemala and not to those of its Political Constitution, which take[s] precedence over any law or treaty’.  

The reservation was controversial. Seven states (Austria, Belgium, Denmark, Finland, Germany, Sweden and the United Kingdom) objected on the basis that Article 27 set out a universally-accepted norm based on customary international law and that the reservation was therefore incompatible with the object and purpose of the Convention. Article 27 codifies the customary rule that states must enter into and perform treaties in good faith. A state cannot escape the obligations it has voluntarily entered into under a treaty by claiming that its domestic laws prevent it from doing so.

In the 28 years in which the reservation was in place, it was never invoked by the Guatemalan government or courts. On the contrary, the Constitutional Court of Guatemala has applied Article 27 in its reasoning without mentioning  the reservation.  The Inter-American Court of Human Rights and international tribunals appointed to determine trade and investment disputes with Guatemala have applied Article 27, without objection by Guatemala (e.g. Case of Chitay Nech and Case of Maritza Urrutia in the IACHR; and WT/DS156/R  para 8.83; WT/DS60/R para 7.38 before the WTO). Meanwhile, Guatemala has strictly applied the principle in Article 27 in its dealings with other countries. For example, Guatemala argued that El Salvador (which is not a party to the Vienna Convention) could not use judgments of its Constitutional Court as an excuse for non-compliance with Central American Integration instruments.

As the reservation to Article 27 was out of step with customary international law and Guatemala’s own practice, the President of Guatemala formally withdrew the reservation on 27 March 2025. Notice of the withdrawal was provided to the United Nations Secretary General on 10 April 2025.

The political reaction

Guatemalan politics is deeply divided. President Bernardo Arévalo won 61% of the vote in the 2023 presidential election. He had campaigned to fight the corruption that has compromised many government institutions and entrenched inequality. Despite the clear election result, the political establishment – dubbed the ‘pact of the corrupt’ –  sought to prevent him from taking office, misusing the courts and criminal prosecutions to do so. These efforts were led by Attorney-General Maria Consuela Porras, who remains in office and has been sanctioned for corruption by several states and was named ‘Person of the Year in Organized Crime and Corruption’ in 2023. Powerful vested interests are still represented in Congress and remain opposed to the President and his government. By April 2025, the President had faced 13 impeachment petitions and 6 attempts to remove his immunity from prosecution. Government officials are frequently targeted with criminal prosecution for actions taken to implement government policy.

In this context, the technical legal decision to withdraw the reservation to Article 27 became a hot political issue. Waves of disinformation ensued: it was said that lifting the reservation would allow Arévalo a second term in office; it would mandate legalised abortion and gay marriage; it would impose foreign agendas on economic and social issues; and fragment Guatemala into many different legal systems.  Lawyers on social media claimed the withdrawal was a treasonous violation of Guatemala’s sovereignty. More moderate criticisms focused on the lack of publicity and consultation before the decision was made.

Various associations and political parties filed amparo petitions before the Constitutional Court challenging the withdrawal of the reservation. (Amparo petitions are extraordinary actions to address the violation of constitutional rights by government officials or agencies.) Among the petitioners is Ricardo Rafael Méndez Ruiz Valdes, who has been sanctioned by the United States and the European Union for actions that undermine the rule of law, including intimidating judges and lawyers and obstructing legal proceedings. It seems that at least some of the petitioners are using the legal process to generate political instability.

On 20 May 2025, the Constitutional Court issued an interim decision. It ruled that the withdrawal of the reservation was unconstitutional and ordered that it be provisionally suspended. A final decision of the Constitutional Court is pending. The Court’s reasoning in the interim decision raises three significant issues of international and constitutional law. 

1.      Legal Interpretation: The meaning and effect of Article 27 of the Vienna Convention

The interim decision viewed Article 27 and the reservation through the principle of constitutional supremacy. The Court states that ‘the reservation sought to establish clear limits on the domestic application of international law, which might introduce obligations that are expressly prohibited or incompatible with constitutional mandates’. It asserted that the reservation ‘functions as a safeguard to prevent the state of Guatemala entering into or implementing treaties that contradict its constitution’. The Court even stated that ‘the purpose of the reservation was not to allow the state to invoke the constitution arbitrarily to disregard treaties, but to preserve the constitution’s supremacy within the domestic legal hierarchy’.

As Guatemalan legal experts have pointed out (see here and here), this frames the reservation to the Vienna Convention as a principle of domestic constitutional law, even though it is an act done in international law.

This approach confuses the distinct purposes and operation of international law and domestic constitutional law.  A reservation modifies the international law obligations that the reserving state owes to other parties to the treaty. It is not the place to impose limits on what the government can or cannot do. The place for that is the Constitution itself.

Making or withdrawing the reservation to Article 27 has no impact on constitutional supremacy in Guatemalan law: with or without the reservation, the Constitution remains the supreme law of Guatemala, and the hierarchy of laws within the state is governed solely by the Constitution. In short, the reservation and the Court’s interpretation of it created a problem of constitutional supremacy where none existed.

 Article 27 simply provides that Guatemala cannot excuse itself from meeting its obligations to other states by saying it is prevented from so doing by its own domestic law.  An inconsistency between a treaty obligation and a domestic constitutional provision can be dealt with in a range of ways. State officials can negotiate to change the draft before the treaty is signed. If the treaty is already in place, a state can decide not to enter into the treaty, it can place a reservation to a provision, or it can withdraw from the treaty. States often formally amend laws to be consistent with treaty obligations and domestic courts have developed techniques of interpretation to manage inconsistencies. If compliance with its constitution leads a state to violate a treaty obligation, then the enforcement mechanisms under the treaty may be activated (for example, the state may have to pay damages if it breaches a foreign investment treaty).

Such assessments of constitutionality are done on a case-by-case basis for each new treaty that a state enters. In contrast, the reservation to Article 27 seeks to provide Guatemala with a blanket exception that would allow it to dishonour any of its obligations to another state under a treaty on the basis that it is inconsistent with any provision of its Constitution. This has highly damaging consequences for Guatemala’s international reputation. The Constitutional Court’s ruling removes something that other states, foreign investors and co-operation partners expect: that Guatemala will honour the commitments it makes when it enters an international treaty.

The divisive political context in which this case arises places the Court in a particularly difficult position. Judicial independence in Guatemala is compromised by the distortion of judicial appointment processes and the abuse of criminal proceedings against judges and lawyers, which expose courts to improper influence by political and private interests.  There is a high risk that courts are used as the arena for political contests. In its interim decision, the Constitutional Court seems to have bought into the misunderstandings spread on social media that the reservation and its withdrawal had an impact on the hierarchy of laws under the Constitution. The Court missed an opportunity to resolve the issue by making a clear statement of the meaning and effect of Article 27 of the Vienna Convention. Doing so would make it clear that Article 27 does not ‘override the constitutional order’. All Article 27 does is restate the fundamental rule of customary international law that a state cannot rely on its domestic law to excuse its failure to perform a treaty obligation that the state has voluntarily entered into.

2.      Responsibility: Who decides to withdraw a reservation and how?

[AD1] The petitioners argued that the power to withdraw a reservation rested with Congress. Article 171(l) of the Constitution gives Congress power to ‘approve, before their ratification, treaties, agreements, or any international settlement’ that affect existing laws, transfer powers to the regional level, require significant expenditure or would submit Guatemala to an international jurisdiction or arbitration. The withdrawal of reservations is not specifically mentioned. The Court’s interim decision did not directly engage with this argument, dismissing, for now, a formal role for Congress in the decision to withdraw a reservation.

Article 183(o) of the Constitution gives the President the power to ‘direct foreign policy and international relations, and to sign, ratify and denounce treaties and agreements in accordance with the Constitution’. In 2007, the Constitutional Court held that President Óscar Berger had the power to withdraw reservations to Articles 11 and 12 of the Vienna Convention on the Law of Treaties without the need for congressional approval.  

In the interim decision, the Constitutional Court revisited its 2007 decision and held that it established a precondition: before a reservation can be validly withdrawn, it is necessary to examine whether it is compatible with the Constitution. This, it says, is ‘consistent with the principle that executive acts on the international stage … are subject to constitutional review’. Here, the Court seems to be inserting a role for itself in reviewing and approving foreign policy decisions. This would give rise to a range of practical, institutional and legal questions. Is the government to submit all foreign policy decisions to the Court for its approval? How are foreign policy issues with constitutional implications to be identified in advance and in the abstract? When are such decisions to be made, especially as treaties and other international agreements are subject to protracted negotiations? In its interim decision, the Court sought to distinguish between routine administrative decisions and actions that affect the constitutional structure of the state. But the case before it demonstrates that this is not always obvious: officials regarded the withdrawal of the reservation to be a technical, routine legal matter, while the Court inflated it into a question of constitutional supremacy.  

The extent to which courts can review foreign policy decisions has long been discussed in comparative constitutional scholarship. In some countries, courts are reluctant to adjudicate any legal issues with foreign policy implications. In others, courts have confined judicial review to whether executives have acted within their constitutional powers, without getting into the merits of a particular decision.  The interim decision of the Guatemalan Constitutional Court risks creating a great deal of uncertainty in the administration of foreign policy, impacting Guatemala and the foreign states with which it engages. If the Court is asserting a new jurisdiction to review foreign policy decisions, it needs to be much more clearly defined.

The interim decision also criticises the government’s secrecy around the decision to withdraw the reservation, noting that it was only made public after the decision had been made and the United Nations had been notified. Public engagement is regarded as important to the democratic credentials of law-making. In this case, prior consultation might have provided a less heated environment for legal experts to address misunderstandings about the meaning of Article 27. Open government decision-making does, however, require a degree of trust between the branches of government, which is clearly lacking in Guatemala today.

3.      Remedies

Under Article 22 of the Vienna Convention on the Law of Treaties, the withdrawal of a reservation is effective once the state notifies the treaty depositary, in this case, the Secretary-General of the United Nations. This was done on 10 April 2025.

In its interim decision, the Constitutional Court claimed (without citing any authority) that while international law does not explicitly contemplate the reversal of a withdrawal of a reservation to a treaty, it does not prohibit it either. The Court ordered the Guatemalan government to notify the United Nations that the withdrawal of the reservation had been provisionally suspended. The government complied and notified the United Nations accordingly.

The problem is that there is no procedure to suspend – provisionally or otherwise – the withdrawal of a reservation.  The Constitutional Court of Guatemala has no jurisdiction to create a new procedure governing the actions of other states and the United Nations as a depository under the Vienna Convention on the Law of Treaties.

If the Court issues a final determination that the President’s action in withdrawing the reservation was unconstitutional, what remedies are available? One possible solution is for Guatemala to re-make the reservation, in the same terms as it was made in 1997. Other state parties to the Vienna Convention on the Law of Treaties would then have 12 months to object. If the Constitutional Court requires the government of Guatemala to take this course, other states will have good grounds to object, as they previously did, to uphold the international norm of good faith in the performance of treaties.

The better approach would be for the Constitutional Court to give Article 27 its proper meaning in international law. In international law, Article 27 requires that a state must comply in good faith with treaty obligations. Once this is understood, it follows that Article 27, and any reservation to it, has no impact on the supremacy of the Constitution in Guatemalan law.

Fabia Fernandes Carvalho is Assistant Professor at São Paulo State University UNESP

Monique Cormier is Associate Professor at the Faculty of Law, Monash University

Tomás Daly is Professor at Melbourne Law School, University of Melbourne

Mateo Merchán Duque is a JSD Candidate at the School of Law, New York University

Anna Dziedzic is an Honorary Senior Fellow, Melbourne Law School, University of Melbourne

Violeta Moreno-Lax is a Professor at the Hertie School, University of Governance in Berlin

Elizabeth Shergold is Senior Lecturer in the Faculty of Law, Monash University

Suggested Citation: Fabia Fernandes Carvalho et al, ‘Polarisation, Politics and the Constitutional Interpretation of International Law in Guatemala’ IACL-AIDC Blog (23 October 2025) https://blog-iacl-aidc.org/2025-posts/2025/10/23/polarisation-politics-and-the-constitutional-interpretation-of-international-law-in-guatemala