A federal appeals court in Washington today sided with the Justice Department in vacating a judge’s order to release a Guantánamo Bay detainee who once swore allegiance to al-Qaida but never fought for the group.

The government sought to keep Mohammedou Ould Salahi detained on the ground that his oath of allegiance to al-Qaida made him a part of the organization at the time of his capture. DOJ lawyers abandoned claims that Salahi aided the September 11 terrorist attacks.