A confidential memo sent to US military commanders on the 27th November had warned them that Japanese hostile intentions were suspected. Prompted by alarming decoded Japanese signal intercepts, the following war warning was sent by the US Army Chief of Staff, General George C. Marshall, to all commands:
Japanese future action unpredictable but hostile action possible at any moment. If hostilities cannot, repeat cannot be avoided, the United States desires that Japan commit the first overt act. This policy should not, repeat not, be construed as restricting you to a course of action that might jeopardize your defense….Should hostilities occur you will carry out the tasks assigned in Rainbow Five so far as they pertain to Japan
Some commanders took this warning more seriously than others.
When Admiral ‘Bull’ Halsey took his carrier group to sea on the 28th, some of his fellow officers thought he was ready to start a war. Many of the men were only prepared for routine overnight operation and a quick return to base. They were quickly advised otherwise:
November 28, 1941
BATTLE ORDER NUMBER ONE
1. The ENTERPRISE is now operating under war conditions.
2. At any time, day or night, we must be ready for instant action.
3. Hostile submarines may be encountered.
4. The importance of every officer and man being specially alert and vigilant while on watch at his battle station must be fully realized by all hands.
5. The failure of one man to carry out his assigned task promptly, particularly the lookouts, those manning the batteries, and all those on watch on the deck, might result in great loss of life and even loss of the ship.
6. The Captain is confident all hands will prove equal to any emergency that may develop.
7. It is part of the tradition of our Navy that, when put to the test, all hands keep cool, keep their heads, and FIGHT.
8. Steady nerves and stout hearts are needed now.
G. D. MURRAY, Captain,
U.S. Navy Commanding