“Dozens killed in airstrike at refugee camp in Yemen” reads the headline in The Washington Post. That must be a war crime, right? Not necessarily. It is not always illegal to kill civilians. What is illegal is to target civilians. And there is a difference between killing and targeting.
The issue here is the fundamental IHL principle of proportionality. Civilian deaths and/or property damage must not be excessive when weighed against the military advantage anticipated from striking a military target.
Let me give you two wildly exaggerated examples. First, you want to take out an enemy military command and control center. The military advantage gained in eliminating this target could be immense. But there’s a civilian janitor. However, the death of one civilian is far outweighed by the military advantage of destroying the command and control center. And the janitor is not your target, the building is.
Second example – there’s a sniper on the roof of an eight-story apartment building that is fully occupied by civilians. Can you blow up the building to get rid of the sniper? No. Even if the civilians are not your target, the civilian deaths would far outweigh the military advantage of taking out the one sniper.
Unfortunately for military commanders, there is no neat mathematical formula for determining what constitutes excessive. Current legal thinking on this issue takes into account what the military commander knew or should have known when ordering an attack. In the Washington Post story, a Saudi general “asserted that the rebels were setting up positions in civilian areas and that the coalition had taken fire from a residential area, forcing a ‘decisive response.’” In other words, the air strike was not targeting civilians, it was targeting rebel forces. Still, this does not settle the question of proportionality. Whether there is adequate justification for the airstrike is for a court, or history, to decide but as with so many IHL issues, the answer is not as clear-cut as it first appears.