Malcolm Bull in the London Review of Books:
Waking to find myself a touch genocidal, I would, I imagine, be uncertain how to proceed. An unprovoked attack on my target group with whatever weapon came to hand might take out a few of them, but also bring my venture to a premature end. Reflecting that few are lucky enough to be in a position to do the job themselves, I could either confine myself to advocacy, or else embark on the difficult and protracted business of getting into a position in which I could expect others to obey my orders.
The problematic nature of this project suggests that genocide, if defined (as it is in the UN Convention) as actions undertaken with intent to destroy a specified ethnic, national or religious group ‘as such’, is not a solitary crime. If someone is sitting in their bedroom planning the annihilation of half the population, it is probably better described as fantasy than intent. On the other hand, soldiers who take no prisoners when clearing the survivors out of a bombarded village may have no sense that they are engaged in anything other than a messy military operation, and be quite indifferent to the identity of those they kill. Connecting the genocidal fantasy with the murderous reality is tricky. Genocide is a big-picture, ‘vision thing’; acts of genocide are generally routine police and military actions involving small numbers of people in particular locations. The fantasists will probably have killed no one, and (pace Daniel Goldhagen) none of the killers may share in the fantasy at all.
It is for this reason that prosecuting individuals for genocide has proved extremely difficult.
More here.