There may be no other term in international humanitarian law (hereinafter, IHL) which evokes such debate or controversy as ‘proportionality’. In part, this debate is a result of the nature of the term itself. The broad use of the term ‘proportionality’ in international law, combined with images of an almost scientific balancing of opposing interests on finely tuned scales of humanitarian justice, masks a much more complex and unclear reality. The degree to which contemporary discussion and, with it, the law camouflages the complex moral issues underlying the targeting ‘proportionality’ test is reflected in the fact that conventional law does not actually use the term. Rather, the question ‘at law’ is whether a loss of civilian life or damage to civilian property during the conduct of hostilities is ‘excessive in relation to the concrete and direct military advantage anticipated’.

The difficult questions presented when assessing proportionality during targeting arise in part because society is required to face the reality that ‘[i]n any armed conflict people are injured or killed and property is damaged or destroyed.’ Even more fundamentally, the assessment of ‘excessive’ killing or damage forces a qualitative assessment by ‘civilised’ peoples of the value of human life not only in relation to other humans but also with respect to property and ultimately politically-driven objectives related to the conduct of hostilities. Ultimately, the goal of warfare is to change the ‘mind’ of another state or other political entity. Yet, forcing one's will on another state by violent means inevitably results in civilians being put at risk ‘not because anyone set out to attack them, but only because of their proximity to a battle that is being fought against someone else’.