A catastrophe averted is likely not to be viewed as a catastrophe. A predicted event that fails to materialize is a non-event, something that did not happen, and politicians who expend wealth and lives on something that fails to happen cannot expect to reap the rewards of their decisions. Quite to the contrary, politicians who spend lives and treasure to prevent catastrophes such as genocide are likely to be vilified and punished for their efforts: to the extent that their actions succeed in averting a catastrophe, there is no proof of their success, only of the costs of their efforts. This last point is especially intriguing, and it goes to the heart of the paradox of genocide prevention. Consider the famous case of Winston S. Churchill. H...