FWIW I suspect that a few "dirty bombs" may be quite spectacular enough. Imagine a few Oklahoma City type bombs with a significant amount of radioactive material .... It could be nasty even without a true nuclear bomb - especially since a lot of people are irrational when it comes to anything radioactive.
The simple fact remains that UBL knew he was going to get routed in Afghanistan after the attacks... he had to have plans ready to go.
Possibly. Remember that they had just gotten done with trouncing the Russians, who were much closer and should have been able to project a lot of force into the area, and they still got their clocks cleaned in Afganistan. But he had to realize that we might do better, especially since we had a chance to learn from their experience.
Even without nuclear weapons, there are still quite a few things they might have prepared that could cause significant disruption - even on a 9/11 scale. "Dirty bombs" could easily be part of that, as could chemical and biological weapons. I suspect the first two would be more likely than the latter - not because it's so difficult to put together crude biological weapons, but because anything infectious would have a high probability of "blowback," and because of the technical difficulties of using an agent like anthrax and getting more than a few casualties in the immediate area. (The key to a successful large-scale anthrax attack would be wide dispersal of aerosolized spores - a rather tricky proposition since these are somewhat contradictory goals).
However "dirty bombs" and chemical weapons are quite capable of creating a major crisis in their own right. I'd suspect both of those before either true nukes or biologicals.
"Possibly. Remember that they had just gotten done with trouncing the Russians, who were much closer and should have been able to project a lot of force into the area, and they still got their clocks cleaned in Afganistan. But he had to realize that we might do better, especially since we had a chance to learn from their experience."
Osama bin Laden lashes out against the West: TIME's January 1999 interview
http://www.time.com/time/asia/asia/magazine/1999/990111/osama1.html
We expect Afghanistan to be bombarded, even though the non-believers will say that they do so because of the presence of Osama. That is why we, together with our brothers, live on these mountains far away from Muslims in villages and towns, in order to spare them any harm.
Hit reply too soon..
They defeated the Russians because of Stinger Missiles the CIA gave them to knock down the helicopters. UBL seems to indicate in 1999 that he realized we would not do the same if/when we went into Afghanistan. He had already seen what we did in Iraq in 1991, and remembered how we hit his camps under Clinton.
9/11 was his way of waking us up. He wanted us in the Middle East/Southeast Asia. He wanted us to stir up trouble... he figured it would add fuel to the fire. I don't think he expected quite what we brought, but I doubt he was entirely surprised.