Perhaps at the point in time that genocide is taking place (as now, in Darfur, or a few years ago in Rwanda) the dilemma between doing nothing, and removing the oppressive government by military means, is insoluble; even the best-planned, best-targeted, best implemented sanctions against the Sudanese regime will not stop the slaughter taking place today. On the other hand, if the USAF bombed the Sudanese government into nothingness today, that would also not stop today's slaughter, and although it might (or might not) stop the activities of the Janjaweed sooner than non-violent international pressure, it and arguably would not lessen the total sum of violence, given the capacity of violence to generate an echo.
The only other practical responses are to go to Darfur with bandages (the humanitarian response) or as mediators (the diplomatic response) - neither of which would prevent the atrocities being carried out.
I must acknowledge that my own personal response is simply this: a feeling of total failure with respect to Darfur, a sense of having done nothing. To my shame, I cannot even recall having written a letter to anyone in power.
In this sense then, today's genocide is always insoluble. The only meningful answer to the question "How do we get away from genocide?" has to be "I wouldn't start from here".
I am all ears to learn if there is anything we can do in the present situation, but for me the absolute dilemma of the present must be dissolved in future time. Our scope for action in Darfur is horribly limited, but the possibility of our preventing future acts of genocide is promising. We cannot prevent them all, as perfection is not on the agenda, and climate change is going to make wars over scarce resources (including productive land) more and more likely, but what we can do is affect the ethical framework in which governments function in the future.
For me, the Human Rights Index in the UN is the instrument that I focus my efforts on. It will not bring about a perfect world, but it is an instrument (as opposed to a declaration or aspiration) which is calculated to bring ethical considerations into play in real international politics, as governments consider their standing among their peers. It also opens up a way to bring real non-violent pressure on potentially geoncidal governments before the genocide actually begins, and so offers a way of avoiding the dilemma that genocide presents to us all.