Taranto's lessons were not automatically accepted

Would a more decisive Taranto have made the United States secure Pearl Harbor?

It might have strengthened the warning, but American leaders could still have treated Italy and Japan as fundamentally different cases.

Additional carriers at Taranto could have delivered a much heavier torpedo and bombing attack. A larger carrier force would also have allowed Eagle to undergo maintenance earlier, making her more likely to be available. In this counterfactual, a devastated Italian fleet could neither support operations towards Crete nor inflict the same later demands on British naval strength, leaving more ships available elsewhere. American officers had already warned that Taranto exposed Pearl Harbor's vulnerability. Even a larger Italian defeat might still have been dismissed in Washington on the assumption that Japan posed a different problem.