The other events you sight are determined by political will and human responses. The issue discussed here is technical and scientific. The will to build a nuclear weapon by a bunch of AQ guys running around the mountains of Waziristan does not overcome the technical requirements entailed.
They might also wish to crash a comet into Washington, but the physics just don't allow it.
The AQ guys allegedly purchased these devices from disillusions Russians. They did not make them.
It would not be impossible to make one. There are numerous reports of fissionable material missing from railroad freight yards. The tools available to common people of today are highly more sophisticated that those that were available to the Manhattan project of the 1940s. Never assume that any enemy lacks the technical knowhow to accomplish anything. The time required to stage impressive attacks is generally consumed in preparations, including attendance at schools. Flight schools, or engineering schools. Any real difference?
"The other events you sight are determined by political will and human responses. The issue discussed here is technical and scientific. The will to build a nuclear weapon by a bunch of AQ guys running around the mountains of Waziristan does not overcome the technical requirements entailed.
They might also wish to crash a comet into Washington, but the physics just don't allow it."
Though a nuclear attack is difficult, it is not improbable. Who is helping to build the Iranian nuclear plant? Russia, France, and who knows who else. Do you think the Mullahs can bribe a few of those scientists to assist them?
Probably not, because the Russians and French have so much integrity... \sarcasm If not them, how about the Red Chinese? Didn't the Chicoms pilfer information from Los Alamos? or was it sold to them?
The point is that AQ has the resources to buy the expertise and equipment they need. It is not improbable.