The costly assumption that fleets were safe in harbour

Pearl Harbor is framed less as a single conspiracy than as a failure of judgement shaped by ego, institutional expectation, and familiar assumptions. The same broad error appeared when Scapa Flow's defences were allowed to age before the loss of Royal Oak. Taranto demonstrated that aircraft could reach a fleet inside a protected anchorage, while Mers-el-Kébir showed that even a former ally might attack if political trust collapsed. Harbours concentrated ships and infrastructure but did not remove them from an enemy's operational reach. The lesson is that location is not a substitute for active defence, intelligence, and readiness.