When Reverend Montgomery and Nigel de Gray broke part of the Zimmermann telegram and realized that German U-boats were about to unleash unrestricted warfare on civilian ships, they handed the telegram to Admiral Hall expecting him to pass it on the the Americans. Instead, Hall decided to keep the telegram secret and chose not to warn the Americans. As a result, when the Germans launched their attack, two ships were sunk, which could have been prevented had Hall sent the telegram. In addition, since the message had been completely deciphered at this time, Hall’s excuse of not wanting to send an incomplete message was no longer valid, and he did it for the sole reason of not wanting the Germans to know that their code was broken.

To consider whether this action was ethical or not, we can only consider the hypothetical outcome of the Germans finding out about the broken code and making their codes more secure. The benefit of this is that the two ships wouldn’t have been sunk. However, if the Germans had found a revolutionary encryption as a result of the broken code, it could potentially have cost many more lives while the Allies tried to decrypt messages. If the Germans had invented the Enigma machine in the first world war instead of the second, the Allies might not have broken the code in time to prevent Germany from winning, though the Enigma machine would most likely not have been as effective during WWII. In the case of all hypotheticals, however, it’s impossible to tell what could have happened and compare the costs and benefits to what did happen based on severity of consequences and probability of occurrence. We can only think about what might have happened with either relief or hope.