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[Minimalist]

I'm going from memory here but as I recall in The Rising Sun, Toland dismissed the Pearl Harbor conspiracy nonsense for the very reason that the US and UK were tracking the Japanese invasion fleet on its way to Malaya and anticipated an assault on the Philippines.  They were still working on the theory that an attack on the fleet at Pearl Harbor ( similar to what the British had pulled at Taranto) was not possible because the water was too shallow for aerial torpedoes to be dropped without hitting bottom.  The Japanese found a solution to that problem.

The UK sent Repulse and Prince of Wales to intercept the Jap fleet but it was 1941 and the lesson about capital ships operating without proper air cover had yet to be learned.

By December 8, everyone had gotten that message.