Authorization for Use of Military Force

The Authorization for Use of Military Force (AUMF) became a central legal framework for the United States’ post-September 11 detention policy and for the government’s case against Mohamedou Ould Slahi. The account distinguishes the force Congress authorized from the secret detention and interrogation operation that followed, then follows the AUMF into habeas proceedings where the government’s arguments and the legal test for detention changed over time.

Authorization and its scope

On September 18, 2001, Congress adopted a joint resolution authorizing President George W. Bush to use force against nations, organizations, or persons that had planned, authorized, committed, or aided the September 11 attacks, as well as those that had harbored such organizations or persons. The resolution followed the attacks and the beginning of the United States’ campaign against the Taliban government in Afghanistan. Its stated scope was framed around responsibility for the attacks and those who sheltered the responsible parties.

The account places that authorization alongside a separate secret operation to kidnap, detain, torture, or kill people suspected of terrorism. Slahi describes himself as a victim of that operation, while maintaining that he had committed none of the acts attributed to it. He recounts turning himself in to authorities in Mauritania on September 29, 2001, expecting to be cleared, but instead being questioned there, transferred to Jordan, held and interrogated for eight months, moved to Bagram Air Base for two weeks, and then taken to Guantánamo. The narrative presents this cross-border course as the operation’s practice, not as a power expressly set out in the resolution; Slahi argues that the secret operation had no legal basis.

The changing allegation against Slahi

The government’s initial focus on Slahi was the Millennium Plot, not an alleged role as a senior recruiter for the September 11 attacks. In 2005, Slahi told an Administrative Review Board that Jordanian interrogators had been particularly concerned about his part in that plot. A later connection to the attacks emerged after the capture of Ramzi bin al-Shibh. Bin al-Shibh identified Slahi as a person he had met in Germany in 1999, said Slahi had advised him to travel to Afghanistan for training, and speculated that Slahi was an operative of Usama bin Laden. The account reports this as an allegation conveyed through interrogation, not as an established finding.

By the time Slahi’s habeas petition came before federal court in 2009, the United States was not arguing that he was a major al-Qaeda figure or that he had participated in al-Qaeda plans or attacks. The government’s theory, as later described by the U.S. Court of Appeals for the D.C. Circuit, was that Slahi had been part of al-Qaeda because he swore an oath of allegiance, associated with members, hosted leaders, and referred aspiring jihadists to a known operative. The distinction mattered: the case concerned whether his past allegiance and contacts justified detention under the AUMF, rather than a criminal indictment for providing material support or a claim that he had aided the September 11 attacks.

Habeas review and the abandoned theory

The government had earlier argued that Slahi could be detained under the AUMF on the theory that he had aided the September 11 attacks. It later abandoned that position, acknowledging that he probably did not even know about the attacks. That retreat undercut public descriptions of him as a leading September 11 recruiter, even as the government continued to argue that his relationship with al-Qaeda justified holding him.

Judge James Robertson granted Slahi’s habeas petition and ordered his release. The decision came amid a broader series of Guantánamo habeas cases in which the government had lost thirty-four of forty-six cases by April 1, 2010. The U.S. Court of Appeals for the D.C. Circuit subsequently reversed Robertson’s order and remanded the case for rehearing under a looser standard for determining whether a detainee was part of al-Qaeda. Under that standard, the government no longer had to show that a prisoner was carrying out al-Qaeda orders or directions at the time of capture.

The appellate court carefully described what the government was and was not claiming. It emphasized that Slahi had not been criminally indicted for material support to al-Qaeda, and that the government was not seeking detention on the ground that he aided the September 11 attacks or purposefully and materially supported al-Qaeda forces in hostilities against United States coalition partners. Instead, the government was expected to rely again on his earlier oath, associations, and assistance. The court said that even if those connections did not independently establish membership, they could make it more likely that he remained a member when captured and therefore remain relevant under the revised test.

Legal significance and unresolved limits

The AUMF’s role in Slahi’s case was therefore not a simple determination that he had participated in the attacks Congress named. The government’s abandoned aided-the-attacks theory and its later reliance on alleged organizational membership show how the asserted basis for detention shifted. The legal question became whether earlier allegiance and sporadic relationships could support a conclusion about membership at the time of capture, despite the absence of an allegation that Slahi fought for al-Qaeda or took part in its attacks.

That shift also defines the tension the account draws between the resolution’s stated target and the reach of detention under its name. Slahi’s habeas case tested the government’s interpretation in court, while the appellate ruling altered the standard for evaluating the government’s evidence and returned the case for rehearing. The account leaves the AUMF’s application to Slahi unresolved at that point: the authorization furnished the government’s legal framework, but the dispute over what his history proved—and whether it made him detainable—remained subject to further judicial review.