7 interesting facts about the attack on Pearl Harbor
US intelligence knew an attack was coming
Although often considered a surprise assault, United States intelligence services were aware that Japan might launch an attack on American forces at some point in late 1941 due to failures in diplomacy between the two nations.
The day before the attack, the U.S. Army Signal Intelligence Service had intercepted communication between the Japanese government and its delegation in Washington, D.C., calling for an end to negotiations in a piece of correspondence known as the “Fourteen Part Message.”
However, the specific targets of the Japanese were unknown and, because of security restrictions and communications technology limitations, the warning about the coming conflict did not reach troops in Hawaii until after the attack had ended.
“Through the benefits of hindsight, much has been written about the intelligence failures leading to the attack on Pearl Harbor,” wrote historian Lori S. Tagg for U.S. Army in 2017.
“To be clear, none of the Magic decrypts precisely laid out Japan's intent to attack Pearl Harbor. Nevertheless, U.S. communications security certainly contributed to the failure to inform ground commanders of the potential for attack in a timely manner.”
