Tragic experience indicates that the most sacred obligations are utterly disregarded when their observance means losing the war.
In war, force is used by the belligerents themselves, no effort being made to bring evildoers before a judicial body, each army acting as judge, jury and executioner.
Once war consisted of individual combats between armed men. Later it was waged between lines of men in opposing trenches. Now it is organized slaughter of whole populations.