FWIW, the Doolittle Raid turned out to be more than a morale booster: it pushed Japanese war planners to extend the boundaries it was to gain military control over, and so far overextend themselves. Not surprising they reacted that way as then-Japanese cities were primarily wood and paper construction. I've wondered whether planners in the US had a notion that that might happen. FDR was vague about where those supposedly-impossible-to-carrier-launch bombers came from, claiming they took off in Shangri-la...