Prewar naval mistakes in carriers, destroyers, intelligence, and strategy

With hindsight, what was each major navy's worst decision before the Second World War?

Britain paused carrier construction, Italy neglected destroyer quality, Germany overbuilt its destroyers, the United States mishandled warning information, and Japan attacked a vastly stronger industrial power.

For Britain, the judgment singles out pausing carrier construction as especially damaging. Italy needed better destroyers, Germany designed oversized destroyers as if they were small cruisers, and the United States failed to share warning information before Pearl Harbor. Japan's deepest error was choosing war with an opponent whose industrial base could overwhelm it.