But the intercepts and reports also suggest that Baghdadi has shifted his attention in recent months to crafting an ideological framework that will survive the physical destruction of the caliphate in Iraq and Syria. In addition to his effort to revamp the group’s school curriculum, Baghdadi appears to have been behind a series of missives in recent months that sought to settle ideological disputes between factions of Islamic State fighters.

Viewed together, such actions convey the impression of a disciplined retreat, with Baghdadi helping manage preparations for a shift from caliphate to underground insurgency and international terrorist movement, current and former U.S. officials said.

“Even as they were losing Mosul and Raqqa, we were seeing indications that they were planning to operate anew, as a clandestine organization,” said Nicholas Rasmussen, who served as director of the National Counterterrorism Center before stepping down in December. “As they were being driven out of these places, they were leaving behind a kind of cell structure.”