A lot of people say the attacks came as a complete surprise.

     A lot of people, even now, say that the attack came as a complete surprise. That is simply not true. Oh, the citizenry didn't know about the attack in advance; but the leadership did. Ah, but the leaders wanted to go to war and the public didn't. If the attack was prevented, there would still be no support. There is no real question. You are not fooling anyone. The attack was entirely preventable. The military had already decoded Japanese communications. They knew where and when the attack was to occur. They just needed to manipulate the public.