The impasse and lack of detention options, critics say, have led to a de facto policy under which the administration finds it easier to kill terrorism suspects, a key reason for the surge of U.S. drone strikes in Pakistan, Yemen and Somalia. Renditions, though controversial and complex, represent one of the few alternatives.

“In a way, rendition has become even more important than before,” said Clara Gutteridge, director of the London-based Equal Justice Forum, a human rights group that investigates national security cases and that opposes the practice…

In December 2011, a federal court hearing for another al-
Shabab suspect, an Eritrean citizen named Mohamed Ibrahim Ahmed, revealed that he had been questioned in a Ni­ger­ian jail by what a U.S. interrogator described as a “dirty” team of American agents who ignored the suspect’s right to remain silent or have a lawyer, according to court proceedings.

Later, the Eritrean was interviewed by a “clean” team of U.S. agents who were careful to notify him of his Miranda rights and obtain confessions for trial. Once that task was completed, he was transported to U.S. federal court in Manhattan to face terrorism charges. His American attorneys sought to toss out his statements on the grounds that they were illegally coerced, but the defendant pleaded guilty before a judge could rule on that question.