Weather had one guy actually making the bombs, who was the only working-class dude. (I think he was a mechanic or something; I forget.) When the yuppies tried to make their own bombs, they blew up two or three of themselves.
So it's really a question of whether these radicals are capable of finding anyone competent enough - and further, to then not expose them through their truly stellar infosec. I'm gonna guess this has been the stumbling block, since I guarantee most of these jokers are really hankerin' to bomb some toilets.
edit: regg down again?