Would you sacrifice one life to save a thousand? It is a morally stupefying question that has gone against our societies ethics. Do we favor the collective good over the good of the individual? However ambiguous the answer is during peace, I believe the answer is clear in wartime. The collective good takes precedent. Admiral William Hall knew this to be true when making the decision to keep the Zimmerman telegram a secret.
The implications of the Zimmerman telegram were possibly multiple civilian casualties as a result of unrestricted U-boat warfare. Admiral Hall knew this and weighed his options. He knew if he passed on the information to President Wilson, the Germans would inevitable know that the British had cracked their code. This with the fact that Admiral Hall knew that the U-boat warfare would most likely incite The U.S. to enter the war all factored into his decision to keep the intelligence a secret.
Admiral William Halls decision reminded me of the movie The Imitation Game staring Benedict Cumberbatch. In the final scene after the British cryptanalysis team crack the seemingly unbreakable Enigma code machine, Alan Turing (played by Benedict Cumberbatch) realizes they cannot immediately act on every piece of information, even if it means saving hundreds of life's. In a captivating moment the characters agree that the outcome of the war depends on the secrecy of their work's completion. In closing, I believe that Admiral Hall's decision was ethical in the time and place he made it, even if today we might regard it conversely.