Diplomatic assurances can become a central element of extradition proceedings where there is a risk of torture, inadequate detention conditions, the death penalty or violations of procedural rights. However, the mere existence of an official diplomatic note does not establish that the obstacle to extradition has been removed. This Observatoire ARGA report examines when such assurances can genuinely alter the legal assessment of risk.

The analysis is based on the absolute prohibition of torture and inhuman or degrading treatment. If a real risk remains after the assurances have been assessed, the seriousness of the alleged offence or the interest of States in international criminal cooperation cannot justify extradition. Courts must therefore examine not only the wording of an undertaking, but also the authority of its issuer, its practical feasibility and the individual circumstances of the person concerned.

The report compares several significant cases from 2022–2025. In Liu v. Poland, general and informal declarations were insufficient to remove the established risk. In Kim, by contrast, targeted additional undertakings played an important role, including a specified place of detention, regular diplomatic visits and monitoring arrangements. The Assange materials illustrate the importance of the precise subject of an assurance, particularly an express undertaking concerning the death penalty. Chappell and Wright demonstrates why the revised version of an assurance may be materially different from the document considered at an earlier stage.

Particular attention is given to monitoring after surrender. It is not enough simply to promise access for monitors. The practical questions include whether they can learn the person’s location in time, meet the detainee confidentially, obtain relevant documents and medical information, and trigger an effective response if a problem is identified.

ARGA identifies four interconnected conditions that contribute to the persuasiveness of an assurance: it should address the specific established risk, come from an authority capable of securing the promised conduct, contain sufficiently defined implementation arrangements, and allow anticipated compliance to be meaningfully verified.

The report concludes that diplomatic assurances should neither be trusted automatically nor dismissed automatically as ineffective. Their significance depends on whether the particular undertaking genuinely changes the predicted treatment of the individual after extradition.