Just wanted to point to Robert Wright's chilling argument around targeted assassinations. The morality of predator strikes was really well explore by Jane Mayer, a few months ago. It also turns out that drone strikes may not even be effective:
There's no way of answering this question with complete confidence, but it turns out there are some relevant and little-known data. They were compiled by Jenna Jordan of the University of Chicago, who published her findings last year in the journal Security Studies.She studied 298 attempts, from 1945 through 2004, to weaken or eliminate terrorist groups through "leadership decapitation" -- eliminating people in senior positions. Her work suggests that decapitation doesn't lower the life expectancy of the decapitated groups -- and, if anything, may have the opposite effect.Particularly ominous are Jordan's findings about groups that, like Al Qaeda and the Taliban, are religious. The chances that a religious terrorist group will collapse in the wake of a decapitation strategy are 17 percent. Of course, that's better than zero, but it turns out that the chances of such a group fading away when there's no decapitation are 33 percent. In other words, killing leaders of a religious terrorist group seems to increase the group's chances of survival from 67 percent to 83 percent.