UNHR in Human Rights in Context: Mandatory Pretrial Detention in the Face of the New Judicial Landscape in Mexico
Originally published in Human Rights in Context, September 29, 2025
Prof Dr James Cavallaro and Dr Sofía Galván Puente
With the stated objective of guaranteeing peace and security, the recent constitutional reform on pretrial detention — in effect as of January 1, 2025 — expanded the list of offenses for which mandatory pretrial detention must be applied. In addition to failing to fulfill the purpose for which it was promoted, this reform clearly contradicts international standards on the matter.
Mere accusation of conduct included on the list of mandatory pretrial offenses–even without solid evidence–is sufficient for a person to be imprisoned for months or even years before trial. Granting this power to the authorities expands their range of action, both lawful and unlawful, and thus increases the possibility of it being used arbitrarily.
It is no coincidence that modern societies have developed strict measures and practices to guarantee the rule of and protect individuals’ rights against the State’s devastating power to deprive someone of their liberty based solely on an accusation. In the international sphere, these safeguards are enshrined in human rights law and are fully applicable in Mexico through the implementation of the principle of conventionality control (“control de convencionalidad”). Based on this principle, all authorities must adopt practices or make decisions in light of the obligations contained in the international human rights treaties ratified by Mexico.
In the context of the recent reform of the Judiciary, the arbitrary application of mandatory pretrial detention is likely to intensify. In the face of a compromised judicial independence and the prioritization of political considerations over merit in the selection processes of judges, a clear risk emerges: that the relevant authorities may ignore or fail to fulfill their obligation to apply the principle of conventionality control. As a result, greater challenges will arise in ensuring that the restriction of an accused person's liberty is based solely on the legitimate purposes that justify the application of the most severe measure — and not merely on public outcry for peace and security.
