THE INTERNATIONAL LEGAL OBLIGATION OF DUE PROCESS IN DEPORTATION PROCEDURES: A CASE STUDY ON U.S REMOVALS TO EL SALVADOR AND THE RISK OF INHUMAN TREATMENT

Since February 2025, the US government has taken unprecedented leaps in its immigration policy, exercising mass deportations and facilitating extrajudicial disappearance of people, without due process and without recourse. Deportations of people carried out without guarantees of due process of law raise serious concerns of international law, especially to countries which participate in egregious violations of human rights in their detention centres. For the purpose of this paper, we will examine the apparent arbitrary expulsion of aliens by the current U.S administration, but will refrain from considering any policy motivated by discrimination or any other politically motivated claims.

Due process is a right guaranteed to all by article 14 of the International Covenant on Civil and Political Rights. However, due to US reservations to the ICCPR, and according to Medellín v. Texas (552 U.S 491, 2008), it is not self-executing, meaning US courts may not apply it domestically without legislative action. In addition, as the International Law Commission observed in its Draft articles on the expulsion of aliens (with commentaries – DAEA), and the ICJ in its Ahmadou Sadio Diallo case, “although the expulsion of aliens is a sovereign right of the State, it brings into play the rights of an alien subject to expulsion and the rights of the expelling State in relation to the State of destination of the persons expelled. Thus, the subject matter does not fall outside international law” (§1). 

According to Wolfgang Friedmann’s analysis of general principles of international law, due process consists of “certain minimum standards in the administration of justice of such elementary fairness and general application in the legal systems of the world that they have become international legal standards.” As such, deportation must conform to the law, with fair procedures to protect individuals from arbitrary or unlawful removal. For further reference, we will use expulsion and deportation interchangeably, as the “formal act or conduct attributable to a State by which an alien is compelled to leave the territory” (article 2, DAEA). 

In an effort to examine the case of U.S removals to El Salvador, and the risk of inhuman treatment, we must first consider the prohibition of arbitrary detention, and then the international obligations of due process in deportations. 

I/ PROHIBITION OF ARBITRARY DETENTION AND OBLIGATION TO RELEASE

Arbitrary detention is unequivocally prohibited by international law, and while its prohibition (Article 9 of the ICCPR) is closely linked to due process obligations in deportations, it remains distinct. The United Nations Working Group on Arbitrary Detention considers there are 5 situations when arbitrary detention may be characterized (Fact Sheet No. 26): (1) absence of any legal basis; (2) deprivation of liberty as a result for exercising fundamental rights; (3) violation of the international rights to a fair trial; (4) subjected to prolonged administrative immigration without the possibility of administrative or judicial review, or remedy; (5) when deprivation of liberty is a result of discrimination. 

Arbitrary detention can be characterized when contrary to domestic law or, as according to HRC General Comment 35, may be authorized by domestic law and nonetheless be arbitrary. It is then characterized by elements of inappropriateness, injustice, lack of predictability and due process of law, as well as elements of reasonableness, necessity and proportionality. Interestingly, the HRC found that detention “in the course of proceedings for the control of immigration is not per se arbitrary”, if they are characterized by the above elements in light of the circumstances, “and reassessed as it extends with time” (§ 18). Detention beyond security motives, if their case for legal immigration is being processed, would then violate article 9. 

As such, detention must not be a capricious or punitive measure, and should serve a legitimate purpose respecting due process. Article 9(4) of the ICCPR grants detained individuals the rights to contest the legality of detention before a judge. General Comment 35 takes this further by considering that the right to take proceedings before a court for release from unlawful detention includes the right to release from detention that is arbitrary within the meaning of article 9, even if it does not violate domestic law (§ 44). Additionally, it found that practices that render judicial review for release unavailable to the individual, including incommunicado detention, also amount to a violation (§ 46). 

In the case of persons deported from the US to El Salvador, on March 15^th 2025, the US authorities flew more than 200 people – including but not limited to Venezuelans purportedly subject to a presidential proclamation invoking the Alien Enemies Act— to be held in the Black Site detention in El Salvador: Centro de Confinamiento del Terrorismo, i.e. CECOT. Prior to their forced rendition, many of these people were either living in immigration detention or at liberty within the United States. Although the administration has stated that these people were terrorists or gang members, it has set forth no credible evidence supporting this assertion. Many of the people rendered to El Salvador had not been convicted of any crime, and reporting has demonstrated that these designations are likely flawed. Defending its policy decision, the US administration has stated these individuals “should stay there for the rest of their lives” (RFK v. D. State§55). On a similar issue in January 2025, the UNHCR held Australia accountable for the arbitrary detention of asylum-seekers it had transferred to Nauru for offshore processing, and that such practice of outsourced detention does not absolve the original state of responsibility. 

In cases where detention procedures overextend reasonableness and legality, Courts and the HCR have instructed the release of those detained. To not release those arbitrarily detained while awaiting deportation or consigned to abusive detention constitutes egregious violations of their rights by the States party to the ICCPR. The detentions of the 200 persons sent to CECOT extend beyond immigration detention, their deportation to the Black site being the only characteristic which may even qualify as such. Their initial detention was arbitral and violated due process. Under its Agreement with the U.S Administration, El Salvador has committed to accept individuals rendered from the U.S.A and to hold them, incommunicado (RFK v. D. State§3), in violation of article 9(4) of the ICCPR, as previously demonstrated. Had due process guarantees in deportation been respected, those 200 individuals may have invoked the principle of non-refoulement to contest transfer to CECOT.

II/ DUE PROCESS GUARANTEES IN DEPORTATION

The international obligation of due process in matters of deportation of foreign nationals, and possible illegal aliens, is confirmed by the previously mentioned Diallo Merits case, where the Court found that Mr. Diallo’s arrest and detention were arbitrary within the meaning of Article 9(1) of the ICCPR (prohibition of arbitrary arrest and detention). The DRC’s authorities refused to provide any grounded and defensible basis for an expulsion measure (§ 80-82). Guinea had argued that the expulsion constituted violations of Article 13 of the ICCPR, which provides that an alien “lawfully in the territory” of the State shall only be expelled pursuant to a decision reached “in accordance with [the] law, and that the alien can request review by competent authorities of this decision, unless there are compelling reasons to deny this appeal”. The Court, finding the decision was not taken in accordance with Congolese law, argued that the expulsion “must not be arbitrary in nature” and that “the protection against arbitrary treatment lies at the heart of the rights guaranteed by the international norms protecting human rights”. As such, the Court, referring itself to the Human Rights Committee General Comment N°15 (1986), finds that by “allowing only those [expulsions] carried out in pursuance of a decision reached in accordance with [the] law, its purpose is clearly to prevent arbitrary expulsions”. Though the extent of that protection is contested by members of the Bench, as it seemingly protects those from arbitrary detention with intent to arbitrary expulsion, but not the latter as a result of the former. The HRC also considered that the “particular rights of article 13 only protect those aliens who are lawfully in the territory of a State” (§9). 

Returning to our case, Article 9 of the DAEA prohibits the collective expulsion of aliens, unless due process is respected for each individual case, meaning that detention is not arbitrary, the individual has been informed of the reasons of his detention and/or expulsion, and has been given the chance to contest the basis on which the competent authority has made its decision. Since February 2025 US officials have carried out arbitrary removals of individuals to El Salvador without a full hearing or judicial process by invoking extraordinary executive powers. Additionally, due process guarantees the deportees the right to an effective remedy if they are at risk of persecution or gross violations of human rights at their arrival, and allow for the competent authorities to halt their removal. Such a right aims to prevent deportation to sites such as CECOT. 

Non-refoulement is a core principle of international human rights from Article 3 of the UN Convention against Torture (and codified into US law at 9 USC §1231), and prohibits States from transferring or removing any person from their jurisdiction or effective control when there are substantial grounds for believing that the person would be at risk of certain serious human rights violations. The principle of non-refoulement is absolute and affords protection to every person of the threat they may pose to the national security of the sending country, and regardless of whether they committed serious crimes, and is linked to articles 6 and 7 of the ICCPR by the HRC General Comment 31 (2004, § 12). Though the CAT article 3(1) exclusively concerns measures of torture, the HRC found that infliction of cruel, inhuman or degrading treatment or punishment, constitute an indication that the person is in danger of being subjected to torture if deported to a State with an existent and consistent pattern of gross, flagrant or mass violations of human rights. The violation of due process in its expulsion of aliens by the current U.S administration violated the principle of non-refoulement. 

III/ INHUMAN TREATMENT OF DETAINEES AND DEPORTED PEOPLE IN EL SALVADOR

Human rights organizations estimate that since 2022, over 350 people have died in El Salvador’s prison in an effort of mass incarceration without due process. These organizations have documented practices of police beating new arrivals in the prisons, prisoners detained in dark cells without access to food or water, overcrowded cells forcing prisoners to sleep standing up, prisoners being forced to kneel on the ground naked for hours, etc. El Salvador officials have reportedly stated that the only way out of CECOT “is in a coffin” (RFK v. D. State§40). According to US officials, those deported to this facility are treated the same way as other prisoners (§ 52). Human rights organization and the US department has produced evidence of widespread torture, inhumane and degrading punishment in this facility (§ 19). 

As El Salvador is detaining individuals solely at the US’ behest and without its own legal process, the detention of the deportees may be considered arbitrary under international law and violating article 9 of the ICCPR. Secondly, as we noted earlier with the Australian case, the offshore penal process does not void the US administration of responsibility in the treatment of these detainees. Lastly, in the case of Abrego Garcia, the US administration blatantly violated due process and international law, as a court order protected him from expulsion pending legal review after an arbitrary arrest and detention. These transfers of individuals have been conducted without regard for legality towards domestic or international law, in a similar manner as the transfer of immigrants scheme between the UK and Rwanda, which the UK’s Supreme Court in 2023 found unlawful due to lack of security and protection concerns, particularly against risk of discrimination, and on the deportation arrangements between Uganda, Rwanda and Israel, where the latter sent asylum seekers to the two countries, without guarantees of fair treatment at their arrival. 

In conclusion, the U.S’ efforts to deport persons, legally present or not in its jurisdiction, to prisons in El Salvador, are in clear contravention of international law, as they are depriving them of liberty and of their right to appeal their case before judicial authorities, whilst being arbitrarily detained in a third-country, without a hint of review or eventual release, and with a high risk of abuse, torture and mistreatment. Due process and human rights are not optional, and these obligations extend to all states.