Steven Pinker is interviewed by Sam Harris, on Sam's increasingly lively blog. It's a great read. This, in particular, was reassuring to me:
It’s an interesting question—almost a philosophical question—whether a single kook with a nuke, or a small number of fanatics with other weapons of mass destruction, would count as displacing the world from its historical trend toward pacifism, if the vast majority of the world were appalled by the destruction and continued its pacific trajectory. A large number of deaths from a single renegade perpetrator would be a misleading indicator of the state of the world. But more to the point, I don’t think that it’s inevitable, or even particularly likely, that a terrorist group will get its hands on a loose nuke or build a garage nuke, nor that it would engineer an epidemic-scale pathogen.