A secret American alert turns Pearl Harbor into a trap

If Roosevelt kept the sighting secret, Enterprise and Lexington could combine while Kimmel prepared the rest of the fleet. The best American timing would catch Japanese decks crowded during launch or recovery, the vulnerability Nagumo historically feared from the missing American carriers. Battleships could sortie before dawn. Aircraft and personnel could disperse under routine-looking cover. The United States could then wait for the Japanese attack before launching its own strike, preserving the political position of having been attacked first.