...Over four years later, there is no doubt. Al-Qaeda is a small terrorist network that has spawned a few copy-cats and wannabes. Its breakthrough was to recruit some high-powered engineers in Hamburg, which it immediately used up. Most al-Qaeda recruits are marginal people, people like Zacarias Moussawi and Richard Reid, who would be mere cranks if they hadn't been manipulated into trying something dangerous. Muhammad al-Amir (a.k.a Atta) and Ziad Jarrah were highly competent scientists, who could figure the kinetic energy of a jet plane loaded with fuel. There don't seem to be significant numbers of such people in the organization. They are left mostly with cranks, petty thieves, drug smugglers, bored bank tellers, shopkeepers, and so forth, persons who could pull off a bombing of trains in Madrid or London, but who could not for the life of them do a really big operation.
The Bush administration and the American Right generally has refused to acknowledge what we now know. Al-Qaeda is dangerous. All small terrorist groups can do damage. But it is not an epochal threat to the United States or its allies of the sort the Soviet Union was (and that threat was consistently exaggerated, as well).
In fact, the United States invaded a major Muslim country, occupied it militarily, tortured its citizens, killed tens of thousands, tinkered with the economy-- did all those things that Muslim nationalists had feared and warned against, and there hasn't even been much of a reaction from the Muslim world. Only a few thousand volunteers went to fight. Most people just seem worried that the US will destabilize their region and leave a lot of trouble behind them. People are used to seeing Great Powers do as they will. A Syrian official before the war told a journalist friend of mine that people in the Middle East had been seeing these sorts of invasions since Napoleon took Egypt in 1798. "Well," he shrugged, "usually they leave behind a few good things when they finally leave."