The U.S. entered World War II in 1941. Yet American planes couldn’t dent a roof in Japan until 1945. The 1942 Doolittle raid, with its 16 bombers that took off from carriers, showed great ingenuity and bravery. But it had zero impact on Japan’s ability to make war.

The raid was designed to boost morale after Pearl Harbor. When the U.S. didn’t follow up with more attacks, the Japanese believed their homeland was invulnerable to enemy bombs because of the emperor’s divine presence. That hubris ended 75 years ago Monday with...