Federal prosecutors' aggressive use of the Material Witness Statute to detain scores of potential terrorism suspects during the decade following 9/11 has been well established by scholars and human rights groups. Details about these detentions have also emerged in criminal and civil litigation, including Ashcroft v. al-Kidd, the first case challenging the government's witness detention practices to reach the Supreme Court. This article posits that the fixation in the literature (and in lawsuits like al-Kidd) on prosecutors' allegedly pretextual use of the statute has overshadowed the complicity of the judiciary in authorizing these arrests and detentions. The provision of the Material Witness Statute - and its relationship to the contempt power - make clear that, despite prosecutors' efforts to co-opt the statute as a law enforcement tool, the authority to arrest and detain material witnesses is a judicial power. As such, the factors that prompted judicial acquiescence in these cases require greater scrutiny. Judges who signed material-witness arrest warrants repeatedly departed from longstanding precedents that defined flight risk in the material-witness and bail contexts. Despite the fact that material-witness detentions should not involve considerations of dangerousness, many of these witnesses were incarcerated for weeks or even months in highly secure facilities pursuant to protocols reserved for the most dangerous pretrial detainees. This article considers two factors that may have influenced these judicial decisions: cognitive biases and excessive pressure to defer to the executive branch. These cases offer an opportunity to evaluate claims made by scholars in the ongoing debate about the degree to which judges do and should defer to prosecutors in cases implicating national security interests. Finally, this article outlines preliminary proposals intended to reinvigorate the judiciary as a meaningful check in material-witness cases and more broadly in the criminal justice system. (Published Abstract)