Whereas bin Laden preached big dramatic acts directed by him and senior Qaeda leaders, al-Suri urges the creation of self-generating cells of lone terrorists or small groups in his 1,600-page Internet manifesto. They are to keep up attacks, like multiplying fleas on a dog that finds itself endlessly distracted—and ultimately dysfunctional. (A classic Western book on guerrilla warfare called The War of the Flea reportedly influenced al-Suri.) The attacks are to culminate, he hopes, in acts using weapons of mass destruction.
Recent terrorist attacks against U.S. targets, from the murderous 2009 spree of Army Maj. Nidal Malik Hasan at Fort Hood to the Boston Marathon bombings last year, suggest that al-Suri's philosophy dominates al-Qaeda's newly flattened hierarchy. The late Yemeni-American imam Anwar al-Awlaki, who preached this strategy and induced Hasan's attack, is said to have developed his ideas from al-Suri's. Meanwhile, with new refuges in North Africa, Syria, and Yemen, jihadists have much more territory from which to hatch plots unmolested.
Yet the politics at home are changing as the threat abroad is growing. The revelations dribbled out by fugitive leaker Edward Snowden have outraged members of Congress and world leaders, including those of close allies such as Germany and France. They say they are aghast at American overreach. Writing in Der Spiegel, Snowden justified himself this way: "Instead of causing damage, the usefulness of the new public knowledge for society is now clear, because reforms to politics, supervision, and laws are being suggested." Thanks to him, Congress will almost certainly rein in the National Security Agency's data-trolling methods—though it's not yet clear how much.
But the agency's opponents may not realize that the practice they most hope to stop—its seemingly indiscriminate scouring of phone data and emails—is precisely what intelligence officials say they need to detect the kinds of plots al-Suri favors. For the foreseeable future, al-Suri's approach will mean more terrorist attacks against more targets—albeit with a much lower level of organization and competence. "It's harder to track. Future attacks against the homeland will be less sophisticated and less lethal, but there's just going to be more of them," says Michael Hayden, the former NSA director who steered the agency after 9/11 toward deep dives into Internet and telephonic data. Adds Mike Rogers, chairman of the House Intelligence Committee, "I think al-Qaeda's capabilities for a strike into the United States are more dangerous and more numerous than before 9/11." For better or worse, the only hope to track them all is an exceptionally deep, organized, and free-ranging intelligence apparatus, experts say.
Intelligence officials who are well briefed in the technical aspects of NSA surveillance also note that global communications are vastly more complex than they were as recently as 9/11, not just in terms of speed and bandwidth but also in the kinds of digital paths they can take. Messages can travel partly by air and partly by cable, for example, and the NSA must keep up. "If you take the diffuse physical environment [of more failed-state havens] and you layer that with the diffuse communications environment, and then you layer that with the diffuse ideological environment—more lone wolves, for example—that makes for a far more generally dangerous environment," says a knowledgeable U.S. government official who asked to remain anonymous.