Pearl Harbor was not about war with Japan -
It was about war with GERMANY
HITLER WOULD NOT DECLARE WAR IF U.S. UNBEATABLE
1)OBJECTIVE:War with Germany.How do you get Hitler to declare war on you? You don't get it by looking unbeatable!
2)Direct efforts in Atlantic had failed.
3)Roosevelt knew from magic that if Japan attacked, Germany would declare war.
4)Therefore: the problem was how to maneuver 4)Japan into firing the first shot or make the first overt act.
5)Japan must succeed or Hitler would renege.

Eric Nave, a British cryptologist worked on the Japanese JN-25 naval code. Nave wrote "Betrayal at Pearl Harbor"
http://www.fff.org/freedom/1291d.asp,
a book claiming Churchill hid what he knew about the attack from Roosevelt.

In the early 1990s the U. S. Navy transferred all its cryptologic archives from Crane, Indiana to the National Archives in Washington. This includes 26,581 JN-25 intercepts from I September to 7 December. http://www.cnrs-scrn.org/northern_mariner/vol12/nm_12_1_17to37.pdf
All of these are available for public review.

http://www.donlinke.com/drakula/vlad.htm