Guarding the USA and Its Outposts

CHAPTER VII
The Pearl Harbor Attack
Guard US Chapter 7
For the first half of 1941 the military strategy and preparations of the United States were aimed toward belligerent participation in the Atlantic war and maintenance in the Pacific of a defensive posture based on Alaska, Hawaii, and Panama. Then, during July, Pacific strategy and preparations began a rapid shift that profoundly affected the outlook and thinking of American commanders both in Washington and in Hawaii. Through decoded intercepts, Washington knew early in the month that Japan had decided upon further aggression to the south. In the light of this knowledge, during the last week of July the United States decided to try to defend the Philippines in the event of war with Japan, and at the same time it applied stringent economic sanctions against Japan which were intended to deter the Japanese but which actually had the opposite effect.