Counterterrorism, Investigative Detention, and the New Global Security Environment

Detention is among the most invasive and potent exercises of government power over an individual. Investigative detention — the pre-charge detention of a suspect for the purpose of obtaining evidence for use at a subsequent criminal prosecution. This differs from other kinds of detention that are relevant to counterterrorism operations (such as battlefield detention under the law of armed conflict) in that it is a detention power that exists within the ordinary, domestic criminal law frameworks of various jurisdictions. This paper explores the international and domestic legal developments related to investigative detention as it is carried out in the United States, the United Kingdom, and France. As part of this discussion, I explain the evolving threat environment that features investigative detention. This paper discusses the way in which each legal regime — based on its respective legal tradition and history — shapes the way in which investigative detention is exercised. Relatedly, this paper also highlights the way in which international law has served as a vector for change and convergence among these otherwise divergent legal systems — creating a rough similitude in the evolving approaches of the United States, the United Kingdom, and France to the problems associated with the investigative detention of terrorist suspects.