The conduct of hostilities in urban areas is inherently difficult, particularly with respect to the protection of civilians. International humanitarian law places restraints on both attackers and defenders. While much is written about the obligations of attackers with respect to protecting civilians, much less attention has been paid to the defender's obligations. These obligations are routinely referred to as “passive precautions” or “precautions against the effects of attacks” and are codified in Article 58 of Additional Protocol I to the 1949 Geneva Conventions. Article 58 requires parties, “to the maximum extent feasible”, to remove civilians and civilian objects from the vicinity of military objectives, to avoid locating military objectives within or near densely populated areas, and to take other necessary precautions to protect civilians and civilian objects from the dangers resulting from military operations.

Even though they are limited by only requiring those actions which are feasible, the obligations placed on the defender are far from trivial and, if applied in good faith, would certainly provide much needed protections to civilians in armed conflict, particularly in times of urban conflict. However, this ever-increasing urbanization is creating significant pressure on the doctrine of precautions in defence, stretching the “feasibility” standard beyond its capacity to adequately protect civilians. On the other hand, the emergence of advanced technology provides a mechanism for defenders to more easily and more fully comply with their obligations to segregate or protect the civilian population.

For the customary obligation of “precautions against the effects of attacks” to maintain its effectiveness, particularly in urban areas of conflict, the understanding of feasibility and what is “practicable” in current urbanized armed conflicts will have to expand, increasing the practical responsibilities on the defender, including through the use of modern technology. Moreover, imposing criminal responsibility when appropriate and feasible precautions are not taken will rectify the perceived imbalance between the responsibilities of the attacker and those of the defender.