The detention facility at Guantánamo Bay was established by the United States (U.S.) following the 11 September 2001 attacks and has remained in operation ever since. It remains one of the most contested detention facilities in contemporary international law. The detention facility, as part of the U.S. counterterrorism regime, has sparked ongoing legal debates regarding the relevance of international humanitarian law (IHL), international human rights law (IHRL), and domestic constitutional protections.
The facility’s operations serve as an important case study for examining how international law functions when faced with claims of security necessity made by a powerful state. This insight examines the legal foundations of the Guantánamo detention regime, the U.S.'s justifications, and the broader implications for the credibility and enforcement of international law.
Following the U.S. military intervention in Afghanistan in 2001, approximately 780 detainees captured during counterterrorism operations were transferred to Guantánamo Bay. As of April 2026, 15 detainees remain in custody, while the others have been released. Out of 15, 7 detainees are facing charges for alleged war crimes and are currently in pre-trial proceedings, and 2 have been convicted. In addition, 6 detainees are held in law-of-war detention without charges, of whom 3 have not been recommended for release by the administrative review board, while the remaining 3 have been recommended for transfer to another country, subject to security arrangements.
The detainees were categorised as “unlawful enemy combatants” by the Bush administration in 2002. This specific classification was deliberate as it distinguished them from both traditional prisoners of war (POW) and ordinary criminal suspects.
This categorisation was controversial because it did not explicitly exist within the legal framework of the Geneva Conventions (GC). Under the GC III, individuals captured in an international armed conflict are generally entitled to POW status, and in non-international armed conflicts, they are protected under Common Article 3 of the GCs. By denying detainees this protected status and, at the same time, declining to process them through ordinary criminal courts, the U.S. created a detention category that operated outside the existing international legal framework.
The detention regime was therefore seen by many scholars and human rights organisations as an attempt to create a “legal black hole”. A jurisdictional space where individuals could be detained indefinitely without the full protections of either humanitarian law or domestic criminal law.
The U.S. primarily justified the detention regime on the basis of domestic wartime legal authorities. Central to this argument was the Authorisation for Use of Military Force (AUMF) of 2001, through which the U.S. Congress authorised the President to use necessary force against those responsible for the September 11 attacks. The U.S. officials contended that the conflict with the transnational terrorist organisation is not subject to the regulations of the Geneva Conventions.
A key aspect of the Guantánamo strategy was the selection of the facility’s geographical location. It was established on a U.S. naval base in Cuba, over which the U.S. had full jurisdiction and control under a long-standing lease, but the territory remained officially outside U.S. sovereign borders. The decision to detain individuals at Guantánamo rather than within the U.S. reflected both legal and political considerations. By holding detainees outside the mainland, the U.S. government initially sought to limit access to constitutional protections and federal courts.
If detainees had been brought directly to the mainland U.S., they would likely have been subject to the full procedural guarantees of the U.S. criminal justice system, including prompt judicial review and formal criminal charges. Guantánamo, therefore, was supposed to serve as a strategic legal buffer, enabling the government to pursue a detention framework it believed better suited to wartime counterterrorism operations.
However, the U.S. domestic judicial intervention significantly altered the legal landscape surrounding Guantánamo. In Rasul v. Bush (2004), the U.S. Supreme Court ruled that federal courts possessed jurisdiction to hear habeas corpus petitions from Guantánamo detainees. Subsequently, in Hamdan v. Rumsfeld (2006), the court held that the original military commission system established by the executive branch violated both U.S. law and the Geneva Conventions. Finally, in Boumediene v. Bush (2008), the Court affirmed that detainees at Guantánamo possessed a constitutional right to challenge their detention through habeas corpus.
These rulings did not abolish the detention regime but introduced important legal restrictions. It showed that constitutional law still exerts influence even beyond territorial boundaries, and that detainees cannot be stripped of the protections under the Geneva Conventions.
International institutions also responded critically to the Guantánamo detention framework. Reports by the United Nations Human Rights Council and the Office of the High Commissioner raised concerns about the indefinite nature of detention, the lack of judicial oversight, and interrogation practices. The international institutions argued that the lack of regular judicial review and the prolonged detention of individuals without trial constitute violations of IHRL and IHL obligations.
Despite these criticisms, it is important to note that no international tribunal issued a definitive ruling declaring the existence of the Guantánamo facility itself unlawful. Instead, legal scrutiny focused primarily on the conditions, procedures, and duration of detention. However, the facility remains controversial, and the absence of any tribunal finding does not confer legitimacy.
The facility's long-term purpose and effectiveness also remain subject to debate. While many former detainees were released or resettled, some, including Abdul Qayyum Zakir, Khairullah Khairkhwa, Noorullah Noori, Abdul Haq Wasiq, and Mohammad Fazl, later emerged in senior positions within the Afghan Taliban or affiliated militant groups. This raises questions about the facility's overall purpose, strategic effectiveness, and long-term consequences.
Although Guantánamo is frequently cited as an example of a powerful state reshaping legal frameworks to achieve security goals, the detention regime still faces notable limitations. Ranging from domestic judicial rulings, sustained criticism from international institutions, diplomatic pressure from allied governments, to reputational costs linked with prolonged detention practices. Over time, these pressures have led to policy adjustments, detainee transfers, and ongoing debates within the U.S. regarding the facility’s future.
Guantánamo Bay reflects how security imperatives can challenge the rules-based international order. While international law applies equally in principle, its enforcement reflects power asymmetry. However, even under such conditions, legal norms cannot be entirely displaced, as prolonged scrutiny and institutional resistance continue to impose limits over time.