Magic (cryptography) - Dewey and Marshall

Dewey and Marshall

During the 1944 election, Thomas Dewey threatened to make Pearl Harbor a campaign issue, until General Marshall sent him a personal letter which said, in part:

To explain the critical nature of this set-up, which would be wiped out in an instant if the least suspicion were aroused regarding it, the Battle of Coral Sea was based on deciphered messages and therefore our few ships were in the right place at the right time. Further, we were able to concentrate our limited forces to meet their naval advance on Midway when otherwise we almost certainly would have been some 3000 miles out of place. We had full information on the strength of their forces.

Dewey promised not to raise the issue, and kept his word.