Chapter 5 – Rules of Combat

Section 1
Attacks

1. An attack is an act of violence against the enemy, whether in the context of offensive or defensive military operations.^{Footnote 17}  Three primary rules govern attacks: distinction, precautions and proportionality. CAF members must apply the primary rules to all attacks against the enemy.

Distinction

2. The rule of distinction requires that CAF members do everything feasible to verify that attacks are directed against people or objects that may be lawfully attacked under LOAC.

3. As explained in Chapters 3 and 4, the following people and objects may be lawfully attacked:

• combatants (unless hors de combat);
• civilians directly participating in hostilities (only for such time as they do so); and
• military objectives.

4. CAF members must cancel or suspend an attack if they become aware that the person or object to be attacked is in fact protected. If in doubt, CAF members must consider the person or object as civilian and must not attack.^{Footnote 18}

Precautions

5. The rule of precautions requires that CAF members take all feasible measures to avoid and, in any event, to minimize incidental loss of civilian life, injury to civilians and damage to civilian objects – “collateral damage” – when conducting attacks.

6. Depending on the operational circumstances, examples of such measures could include:

• conducting an attack at a time when civilians are less likely to be present; or
• choosing a weapon that is less likely to cause collateral damage.

7. The rule of precautions also includes the requirement to provide the civilian population with advance warning of attacks that may affect them, unless operational circumstances do not permit. In some cases, the need to maintain the element of surprise may mean that the CAF cannot give a warning.^{Footnote 19}

8. CAF members must also take all feasible measures to protect civilians and civilian objects against the dangers of enemy attack. To the extent that operational circumstances permit, CAF members must avoid locating themselves, their equipment or their facilities within or near densely populated areas and must attempt to remove civilians and civilian objects from the vicinity of CAF operations.^{Footnote 20}

9. The rule of precautions recognizes that it will not always be possible for CAF members to avoid collateral damage altogether when attacking. The mere fact that an attack may cause collateral damage does not necessarily make the attack unlawful under LOAC. However, CAF members must ensure that the attack complies with the rule of proportionality.

Proportionality

10. The rule of proportionality requires that CAF members refrain from conducting attacks that are expected to cause collateral damage that is excessive in comparison to the specific military advantage anticipated. There is no mathematical formula for determining proportionality. Ultimately, CAF members must make each assessment honestly and reasonably based on the relevant information available at the time, weighing the military interests anticipated to arise from the success of the attack on the one hand, against the expected civilian casualties and damage to civilian objects on the other.^{Footnote 21}

11. CAF members must cancel or suspend an attack if they become aware that collateral damage that was initially expected to be proportionate is likely to be excessive.^{Footnote 22}

Section 2
Other Tactics of Warfare

12. In addition to the primary rules of attack, LOAC also sets out other rules that complement or reinforce the primary rules and reflect LOAC’s balancing of military necessity and humanity. For instance, LOAC prohibits certain tactics of warfare that undermine or are otherwise inconsistent with the concept of humanity and the protection that LOAC affords to civilians and combatants who are hors de combat.

Perfidy

13. LOAC prohibits killing, wounding or capturing the enemy by resort to perfidy. Perfidy involves inviting the enemy to believe that they are entitled to or are obliged to grant protection under LOAC, with intent to betray that belief (e.g. feigning intent to surrender; feigning incapacitation by wound or sickness; or feigning civilian status).

14. Perfidy is not to be confused with ruses of war. Ruses of war are permitted under LOAC. Ruses of war are acts that are intended to mislead the enemy but do not invite the enemy to believe that they are entitled to or are obliged to grant protection under LOAC (e.g. camouflage; decoys; mock operations; and misinformation).

Other Prohibitions

15. Other prohibited tactics of warfare include:

• denying or threatening to deny quarter (e.g. ordering, implying or encouraging that no prisoners will be taken);
• improperly using recognized protective emblems, signs or signals, such as the Red Cross/Red Crescent/Red Crystal, the protective emblem of cultural property or the flag of truce; and
• starving the civilian population.

16. LOAC also prohibits or restricts the use of certain weapons and ammunition. These are addressed in Chapter 6.