The atrocities perpetrated by the Islamic State against prisoners of war, western journalists and local minorities have inspired many to call for a military intervention to stop them. Extreme revulsion in the face of these crimes is perfectly natural, but if one is not moved by the deontological case against aggressive warfare then perhaps one ought to consider a utilitarian one. Before countenancing an intervention, come to a determination as to whether or not the present crisis is a product in some fashion of a prior interference. If this is the case, then one ought probably to conclude that interventions in foreign lands have unintended consequences that cannot be factored into the calculations of the interveners. In this respect foreign policy is alike to domestic; government interference has unforeseen consequences which can often be the opposite of those desired. Societies and human interactions are far too complex to be manipulated by central planners and this applies both at home and abroad.