Terrorists do not distinguish between military and civilian targets. Israel, unlike the terrorists, must make this distinction. In yesterday's judgment concerning "targeted killings", the High Court of Justice ruled that the IDF must observe the customary rules of international humanitarian law. These rules, as stated by the court, forbid targeting civilians and civilian objects for attack. Only if civilians are currently and directly engaged in armed hostilities, do they lose their immunity. In such cases the IDF has the clear duty to stop them - by arrest, if possible, and if not, as a last resort, by killing them. But how do we know if a civilian is protected from being attacked or has forfeited his immunity? The answer given by international humanitarian law is that the civilian can become the object of military attack only during the time that he is actually taking a direct part in hostilities. For example, if someone is loading Kassam missiles on a vehicle, that person is a legitimate target of attack. The High Court of Justice blurred this distinction. It held that even a civilian sitting in his home could be the legitimate target of attack if the IDF believes that he joined a terrorist organization and regularly engages in a series of armed hostilities, or plans them or decides on them. On the basis of military intelligence alone, a person who appears to be a civilian and is not currently taking a direct part in any military action, can be judged guilty and killed. But military commanders are not omniscient and they should not be given the authority to conduct an extra-judicial execution of a civilian. In a curious twist, the High Court of Justice held that an independent examination must be conducted, after the fact, to determine if the "targeted killing" was justified. If it turns out that the military killed the wrong person, or killed someone on the basis of insufficient evidence, the independent examiner will not be able to restore the victim to life or absolve our military from its responsibility for committing a war crime. The writer is legal director of the Public Committee Against Torture in Israel.