VS US General Marshall testifies at Joint Pearl Harbor Committee in Washington, DC

The transcript is a letter addressed to Governor Dewey, marked as top secret and intended for his eyes only. It discusses a grave dilemma related to the political reactions of Congress regarding Pearl Harbor. The letter reveals that the U.S. had intercepted Japanese diplomatic communications, which provided crucial intelligence. However, this intelligence did not indicate any intentions towards Hawaii until after the Pearl Harbor attack. The letter emphasizes the confidentiality of the information and the need for discretion in its handling.

What type of information did the author claim to possess regarding Japanese diplomatic communications?

What was the significance of the last message received before December 7th?