FOUR YEARS AGO, HIS WORDS WOULD have represented an almost unquestioned consensus view. In late January, the State Department's counterterrorism coordinator, Dell Dailey, described al Qaeda's top leadership as isolated, saying that they have "much, much less central authority and much, much less capability to reach out."

He is not alone in this assessment. In July 2007, Stratfor's Peter Zeihan argued that while a few thousand people may claim to be al Qaeda members, "the real al Qaeda does not exercise any control over them. . . . The United States is now waging a war against jihadism as a phenomenon, rather than against any specific transnational jihadist movement." The most prominent proponent of this view has been Jason Burke, a reporter for London's Observer and the author of Al-Qaeda: The True Story of Radical Islam. By the time that book hit newsstands in 2003, Burke was already arguing that the "nearest thing to 'Al-Qaeda,' as popularly understood," only existed for a five-year period, and the battle of Tora Bora in December 2001 showcased "the final scenes of its destruction." Now, Burke contends, we are "in a 'post-bin Laden' phase of Islamic militancy."

Unfortunately, all these men are wrong--and we will fight the war on terror less effectively if we continue to harbor mistaken assumptions about the al Qaeda network. It is important not to overstate what the terror group's leadership needs to do to remain relevant. Even if the central leadership's role is limited to connecting terrorist nodes--pairing skill sets, financing, and operatives--it can transform terrorist groups from disunited regional problems into cohesive adversaries capable of threatening Western societies. Moreover, the safe havens that al Qaeda's leaders have gained in recent years magnify their lethal capabilities.

AL QAEDA ITSELF HAS FACED INTERNAL debates about its future. Abu Musab al-Suri, one of the most prolific jihadist ideologues, in recent years has argued for a decentralized combat model. In contrast, Abu Bakr Naji, another prominent ideologue, calls for a more centralized model.

Suri's 1600-page manifesto, The Call for Global Islamic Resistance, argues that the centralized, hierarchical model of jihadism cannot overcome the U.S.'s technologically advanced military, and that regional security cooperation--such as the alliance between Washington and Islamabad--makes a hierarchical structure dangerous. He suggests that decentralization immunizes terror cells from detection through the capture and interrogation of members of other cells. Suri's prescription for decentralization would mean replacing the old training camp model with one in which fighters are trained "in homes and mobile camps."

In contrast, Naji's The Management of Savagery argues that once the jihadists hold territory, they should erect a governing apparatus to enforce Islamic law and provide security, food, and medical care. A high command would ensure that efforts are not needlessly duplicated, and would prioritize actions against various groups or nations. Naji's argument has carried the day within al Qaeda's hierarchy. Though there are many reasons for this, perhaps the most significant factor has been external events. As al Qaeda gained new safe havens in Pakistan and beyond, Naji's model seemed most fitting.