What is al Qaeda?
Here is a good article on al Qaeda. The author argues that it " is less an organization than an ideology" and that bin Laden "functioned like a venture capital firm—providing funding, contacts, and expert advice to many different militant groups and individuals from all over the Islamic world."
A couple of thoughts/questions.
1. While it is true that the founder of al Qaeda was Abdullah Azzam, bin Laden murdered him in a dispute over the direction the group should take. Citing Azzam's vision of al Qaeda tells us little about the current operations and aims of the group.
2. It is comforting to think that the typical terrorist is too unsophisticated to build a dirty bomb or unleash WMDs. While it may be true that " alleged attempts by a British group to develop ricin poison, but for the apparent seriousness of the intent, could be dismissed as farcical," the same thing could have been said about the initial bombs of the New York terror cell and Timothy McVeigh as well as Atta's dreams of weaponized crop dusters. All three groups learned from their mistakes. In two of those cases, the learning was made possible by al Qaeda.
No, it is not a tightly controlled global network and bin Laden is not the Napoleonic mastermind behind all terrorist operations. But the extreme danger from al Qaeda grows from its organizational and operational capabilities. For a decade it has functioned as a highly effective combination of general staff and think tank for Islamic terrorists.
For instance, it gave the terrorists an institutional memory which prolonged the danger even after key players were imprisoned or killed. We see this with the 9-11 attacks. Ramzi Yousef conceived of the idea and worked out some of the details. Then he was arrested and jailed in a Supermax prison. But al Qaeda (especially Khalid Sheik Mohammad) was able to keep the plan alive and then recruit Atta. In addition, al Qaeda provided Atta with money and recruits to bring the attack off six years after Yousef's capture.
By transferring its knowledge to sympathetic local groups, al Qaeda enabled them to increase their capabilities faster and let them avoid trial and error methods than can draw police attention. (See how Yousef helped the first WTC bomb group). Modern law enforcement pits the collective experience of the police department against the individual learning curve of the criminal. Usually, this makes for short criminal careers. Al Qaeda shifted this balance with systematic training and planning for terrorists.
Even if we capture or kill bin Laden, this new model will remain a danger. On the other hand, the model has vulnerabilities beyond those of conventional terrorists. They need safe harbors, bases to train, compliant or non-functioning states to hide in and travel from. All of these vulnerabilities can be exploited by our law enforcement and military forces.