Re: only if they lost ...
Jus in bello Once war has begun, just war theory also directs how combatants are to act: (Jus in bello)
Distinction Just war conduct should be governed by the principle of distinction. The acts of war should be directed towards enemy combatants, and not towards non-combatants caught in circumstances they did not create. The prohibited acts include bombing civilian residential areas that include no military target and committing acts of terrorism or reprisal against ordinary civilians. Proportionality Just war conduct should be governed by the principle of proportionality. An attack cannot be launched on a military objective in the knowledge that the incidental civilian injuries would be clearly excessive in relation to the anticipated military advantage (principle of proportionality). Military necessity Just war conduct should be governed by the principle of minimum force. An attack or action must be intended to help in the military defeat of the enemy, it must be an attack on a military objective, and the harm caused to civilians or civilian property must be proportional and not excessive in relation to the concrete and direct military advantage anticipated. This principle is meant to limit excessive and unnecessary death and destruction.