The Central Intelligence Agency played a crucial role in US policy during the Soviet invasion of Afghanistan. However, scholars have overly focused on the idea that the CIA promoted a global ‘jihad’. This article instead looks at knowledge-formation within the agency to understand US approaches to the conflict, and to Afghan society more generally. Drawing on recently declassified analyses and reporting from intra-agency departments, this article reveals that agency officials focused largely on the idea of ‘tradition’ to understand the organization and motivations of the Afghan resistance. This trope emphasized Afghanistan's historically ‘tribal’ and ethnically divided nature and presented a static view of an unchangeable, backwards society incapable of coordinating to counter the Soviet military presence. In this reading, officials actually downplayed in the importance of Islam to Afghan society, dismissing it as a potential political force in the region. Ultimately, this article reflects on CIA officials’ limitations in envisioning a post-invasion Afghanistan, finding explanations in their rigid views of Afghan political and social organization which prevented them from recognizing the invasion's potential to catalyze longer-term changes.