Ljubljana–Hague Convention

The Ljubljana–Hague Convention on Mutual Legal Assistance (full name: The Ljubljana – The Hague Convention on International Cooperation in the Investigation and Prosecution of Genocide, Crimes against Humanity, War Crimes and other International Crimes) is an effort to streamline the prosecution of offenders against international criminal law through cooperation between states on matters such as information sharing, extradition, jurisdiction, and the definitions of international crimes.

The Ljubljana-The Hague Convention on International Cooperation in the Investigation and Prosecution of the Crime of Genocide, Crimes against Humanity, War Crimes and other International Crimes is a multilateral treaty adopted on May 26, 2023, in Ljubljana, Slovenia, and opened for signature in The Hague in January 2024. Historically, there has been no comprehensive and uniform framework for inter-State cooperation in addressing core international crimes, as existing instruments, such as the United Nations Convention against Transnational Organized Crime (UNTOC) or the Genocide Convention, have not provided consistent mechanisms. This treaty addresses instruments specifically governing mutual legal assistance and extradition for core international crimes.

The Convention facilitates cooperation among States Parties in investigating and prosecuting the most serious international crimes, It covers:

• Genocide: Trying to destroy a whole group of people.
• Crimes Against Humanity: Widespread terrible acts against civilians.
• War Crimes: breaches of international humanitarian law.

It also has a special list of other serious crimes, like torture or forced disappearances, that countries can choose to include if they want to. This means countries can pick and choose to cover more crimes mentioned in Article 2(2)- States Parties can extend the Convention's scope to other international crimes listed in Annexes A to H, making the rulebook flexible.

It was agreed to by 68 states on 26 May 2023.^[3][4][5]

As of February 2025, it has been signed by the following states:^[6]

Albania,^[7] Argentina, Austria.^[8] Belgium,^[9] Bulgaria,^[10] Central African Republic, Chile,^[11] Costa Rica, Croatia, Cyprus, Czech Republic, Democratic Republic of Congo,^[12] Danmark, Finland,^[13] France,^[14] Germany, Ghana,^[15] Republic of Ireland,^[16] Kosovo,^[17] Liechtenstein,^[18] Lithuania, Luxembourg, Malta, Moldova,^[19] Mongolia, Montenegro, Netherlands,^[20] North Macedonia,^[21] Norway, Poland, Rwanda, Senegal, Slovenia, Sweden,^[22] Switzerland,^[23] Ukraine,^[24] Uruguay.

1. Mutual Legal Assistance (MLA)

It refers to countries sharing information and helping each other gather evidence. Part III of the Convention gives a framework for Mutual Legal Assistance, obligating States Parties to provide the widest measure of mutual legal assistance in investigations, prosecutions, and judicial proceedings for the covered crimes. Article 29 talks about how, for jurisdictions that require a treaty as a prerequisite for mutual legal assistance, the Convention explicitly serves as the legal basis for such cooperation.

The forms include:

• Interviewing the witnesses or experts.
• Looking at crime scenes or objects.
• Sharing information and evidence.
• Searching places and taking things (like evidence).
• Helping people come to court.
• Even using special investigative methods like undercover operations or working together in joint investigation teams.

The Convention also includes provisions for investigative techniques such as special investigative techniques, covert investigations, joint investigation teams, and cross-border observations, which are crucial for investigating complex transnational crimes.

Mutual legal assistance may be refused under specific grounds, they can refuse if they think the request is unfair, like if it is based on someone's race or religion, or if the person might be tortured. But they cannot say no just because it involves the basis of bank secrecy. However, there is a part that gives countries a lot of room to say no to sharing personal information if their own laws stop them or if it would hurt someone's privacy, including if the request is discriminatory, concerns a death penalty without credible guarantees, involves double jeopardy, or risks torture or flagrant human rights violations. While the Article includes safeguards against human rights violations such as protections against torture or death penalty without assurances, it also permits refusal on broad discretionary grounds like national security, public order, or the risk of a life sentence without parole. These exceptions allow States discretion in cooperation, potentially limiting assistance based on domestic concerns.

2. Extradition

Extradition refers to the process by which one State surrenders a person to another State for prosecution or punishment in connection with a serious offence. The Convention says countries must send someone back if the crime is serious enough. Part IV of the Convention outlines the provisions governing extradition. It applies to the covered crimes when the person sought for extradition is present in the territory of the requested State Party.

Countries can say no to sending someone back for similar reasons as refusing help with investigations, like if it is unfair or if the person might be tortured. Article 51 gives grounds for refusal, distinguishing between mandatory and discretionary grounds. Mandatory refusals include discriminatory prosecution, death penalty without guarantees, double jeopardy, or risk of torture/human rights violations. Discretionary grounds include a real risk of life imprisonment without parole, pending domestic proceedings, or if execution would prejudice the requested state's sovereignty or essential interests.

The Convention includes the Rule of Speciality, which generally prevents an extradited person from being prosecuted for crimes other than those for which they were extradited, unless consent is obtained or the person voluntarily remains in the requesting state. Regarding the Extradition of Nationals, the Convention critically mitigates the risk that this principle often creates: Art. 54(1) states that if extradition is refused on the ground of nationality, the aut dedere, aut judicare obligation immediately applies. This means the State Party that refused extradition must then submit the case to its competent authorities for prosecution. The Convention also provides for alternative mechanisms such as conditional extradition. An important aspect in this Convention is that if a country refuses to send its own citizen back, it must then try that person in its own courts. This is significant because it means offenders cannot just hide in their home country and get away with it.

3. Transfer of sentenced persons

Part V gives a framework for the transfer of persons sentenced in one State Party to another to serve their sentence, subject to domestic law and consent of the state parties involved. This mechanism facilitates the enforcement of sentences even if the individual moves or is a national of another state, contributing to the prevention of impunity. If someone has already been found guilty and sentenced in one country, this part of the Convention helps move them to another country like their home country to serve their punishment. This helps make sure sentences are carried out, even if the person moves.

4. Jurisdiction

Article 8 of the Convention mentions how States Parties shall establish jurisdiction when the crimes are committed in their territory or on board their vessels/aircraft, or when the alleged offender is a national of that State. The Convention says a country must be able to try a case if:

• The crime happened in their country.
• The offender is one of their citizens.

A particularly important and highly debated part of the Convention is Article 8(3), which requires a State Party to prosecute an alleged offender found in its territory if it does not extradite or surrender that person to another State or to an international criminal court. This provision is a form of "universal jurisdiction" and is intended to ensure that individuals cannot escape prosecution by seeking refuge in a country that has no direct connection to the crime. During the negotiation of the Convention, some countries, including France and the United Kingdom, strongly objected to this rule, arguing that existing international law does not require a country to establish jurisdiction over all covered crimes based on a person's "mere presence".  

To reach a consensus and allow for the Convention to be adopted, a key compromise was made. While the language of Article 8(3) remained in the final text, a new provision (Article 92(3)) was added that allows States Parties to make a reservation, for renewable three-year periods, to limit the establishment of this universal jurisdiction. This allows a country to say it will only prosecute a person found in its territory if that person is "habitually resident," rather than just visiting.

5. Victim and witness protection

Part VI talks about rights and protection of victims and witnesses. Convention’s preamble recognises rights of victims and protection, witnesses and others involved and  their right to protection, their role in the judicial process. The Act defines victims as natural persons who have suffered harm, and may include organizations that have sustained direct harm to specific property. Article 83 details victims' rights, including the right to reparation for harm, and the right to participate in criminal proceedings, subject to domestic law.

It says countries must:

• Protection of Victims and Witnesses: Keep victims and witnesses safe from harm or threats, maybe even by moving them or keeping their identities secret.
• Right to be heard: Allow victims to share their stories and concerns in court, in a way that does not hurt the accused person's rights.
• Right to Reparation and Compensation: Make sure victims can get help for the harm they suffered, like compensations to help them recover. It even says countries should help enforce court orders from other countries that say victims should get help.

6. Institutional arrangements

The Convention includes provisions for institutional arrangements, such as the designation of central authorities for communication and the convening of Meetings of States Parties to oversee implementation and consider amendments. It also addresses the settlement of disputes, allowing for negotiation, arbitration, or referral to the International Court of Justice, with a provision for reservations to the ICJ mechanism.  

• Ljubljana–Hague Convention: Full text
• Mutual Legal Assistance and Extradition Initiative - Government of Slovenia
• Mutual Legal Assistance Initiative - Government of the Netherlands