<P> Fortunately for the United States, the American aircraft carriers were untouched by the Japanese attack; otherwise the Pacific Fleet's ability to conduct offensive operations would have been crippled for a year or more (given no diversions from the Atlantic Fleet). As it was, the elimination of the battleships left the U.S. Navy with no choice but to rely on its aircraft carriers and submarines--the very weapons with which the U.S. Navy halted and eventually reversed the Japanese advance . While six of the eight battleships were repaired and returned to service, their relatively low speed and high fuel consumption limited their deployment, and they served mainly in shore bombardment roles (their only major action being the Battle of Surigao Strait in October 1944). A major flaw of Japanese strategic thinking was a belief that the ultimate Pacific battle would be fought by battleships, in keeping with the doctrine of Captain Alfred Thayer Mahan . As a result, Yamamoto (and his successors) hoarded battleships for a "decisive battle" that never happened . </P> <P> The Japanese confidence in their ability to achieve a short, victorious war meant that they neglected Pearl Harbor's navy repair yards, oil tank farms, submarine base, and old headquarters building . All of these targets were omitted from Genda's list, yet they proved more important than any battleship to the American war efforts in the Pacific . The survival of the repair shops and fuel depots allowed Pearl Harbor to maintain logistical support to the U.S. Navy's operations, such as the Battles of Coral Sea and Midway . It was submarines that immobilized the Imperial Japanese Navy's heavy ships and brought Japan's economy to a virtual standstill by crippling the transportation of oil and raw materials: by the end of 1942, import of raw materials was cut to half of what it had been, "to a disastrous ten million tons", while oil import "was almost completely stopped". Lastly, the basement of the Old Administration Building was the home of the cryptanalytic unit which contributed significantly to the Midway ambush and the Submarine Force's success . </P> <P> Ever since the Japanese attack, there has been debate as to how and why the United States had been caught unaware, and how much and when American officials knew of Japanese plans and related topics . Military officers including Gen. Billy Mitchell had pointed out the vulnerability of Pearl to air attack . At least two naval war games, one in 1932 and another in 1936, proved that Pearl was vulnerable to such an attack . Admiral James Richardson was removed from command shortly after protesting President Roosevelt's decision to move the bulk of the Pacific fleet to Pearl Harbor . The decisions of military and political leadership to ignore these warnings has contributed to conspiracy theories . Several writers, including journalist Robert Stinnett and former United States Rear Admiral Robert Alfred Theobald, have argued that various parties high in the U.S. and British governments knew of the attack in advance and may even have let it happen or encouraged it in order to force the U.S. into war via the so - called "back door". However, this conspiracy theory is rejected by mainstream historians . </P>

What was the population of pearl harbor in 1941