Since humanity obliges us to prefer the gentlest methods in the prosecution of our rights, if, by a stratagem, by a feint void of perfidy, we can make ourselves masters of a strong place, surprise the enemy, and overcome him, it is much better, it is really more commendable, to succeed in this manner, than by a bloody siege or the carnage of a battle. But the desire to spare the effusion of blood will by no means authorize us to employ perfidy, the introduction of which would be attended with consequences of too dreadful a nature, and would deprive sovereigns, once embarked in war, of all means of treating together, or restoring peace.
—Emerich de Vattel. The Law of Nations, 1758.
The use of deception in war is commendable, as it reduces casualties on both sides. Feints, false radio traffic, the secret decryption of enemy communications, the use of double agents, throwing corpses into the water with false documents in their pockets—these actions are all perfectly compatible with national honor. However, a nation should never treacherously break a truce, smuggle contraband in a hospital ship, use its diplomats as cover for spying, breach a peace treaty, pretend negotiation as cover for a surprise attack, be insincere in putting out peace feelers, pretend distress in order to ambush rescuers, or otherwise act in a perfidious manner.