In the weeks following the events of September 11, 2001, the Bush administration granted the CIA authority to set up detention facilities known as ‘black sites’ outside the United States, and to employ new interrogation procedures on suspected terrorists taken into custody. Recently released legal memoranda by the US Department of Justice’s Office of Legal Counsel condoned the use of several interrogation techniques (such as waterboarding and prolonged sleep deprivation), which the US itself had previously condemned as torture. This paper examines the legal rationalisations the Bush administration advanced to circumvent international and national laws prohibiting torture and other forms of cruel, inhuman, and degrading treatment. It also juxtaposes these rationalisations with medical evidence of the physical and psychological effects of torture and other forms of cruel, inhuman, and degrading treatment. Finally, it recommends several prohibitions and safeguards that the Obama administration should enact to prohibit torture and prevent authorised interrogation techniques from being used in such a way that their cumulative effect results in torture or illegal cruelty. Governments must consider the cumulative effect of interrogation practices and conditions of confinement when creating policies and procedures designed to prevent torture. Long-term political and legal policies must consider both the legal definitions of torture used in international law and the medico-legal evidence that certain interrogation techniques when used together, or in succession and over extended periods, can amount to torture. Finally, the paper calls on the Obama administration to establish an independent, non-partisan commission to investigate and publicly report on the post-9/11 treatment of detainees suspected of terrorist activities who have been held in US custody.