The evidence of ongoing peack talk between the Japan and U.S. was presented to underscore the surprise nature.
The attack was about surprised aerial attack on the U.S. naval base at Pearl Harbor by the Japanese army.
After the attacked, Roosevelt gave a speech that the country will never forget December 7, 1941
In conclusion, the attack was a suprise because Japan and United States were still looking for ways to solidify peace in the Pacific.
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