Bioethicist Peter Singer is on the celebrity philosopher circuit nowadays. He is a syndicated columnist and, along with philosophers like Julian Savulescu and Bernard-Henri Lévy, is on Twitter. He often seems to speak forums organised by universities and think tanks. Recently he addressed a gathering organised by the Carnegie Council.
Somewhat surprisingly, on utilitarian grounds he defended the possibility of imposing the death penalty. At this moment, there exists no situation in which it is needed, even for those convicted of genocide. Theoretically, however, there is nothing wrong with it:
QUESTION: Is there any possible scenario that you could imagine sanctioning the death penalty?
PETER SINGER: Is there any possible scenario where I could imagine? Look, if somebody came up with convincing evidence that the death penalty was a uniquely effective deterrent—let's say that for every murderer who was executed, there would be ten fewer murders—then, as a utilitarian, I would have to accept the death penalty. In fact, if the evidence was clear-cut enough and sound enough, even if it was only for every person executed, there were two fewer murderers or one and a half fewer murderers, I guess I would accept it.