Harbor, heading back. In fact, Enterprise had been scheduled to be back on December 6, but was delayed by weather. A new arrival estimate put her arrival at Pearl around 07:00, almost an hour before the attack, but she was also unable to make that schedule. Furthermore, at the time, aircraft carriers were classified as fleet scouting elements, and hence relatively expendable. They were not capital ships. The most important vessels in naval planning even as late as Pearl Harbor were battleships (per the Mahan doctrine followed by both the U.S. and Japanese navies at the time). Carriers became the Navy's most important ships only following the attack. At the time, naval establishments all over the world regarded battleships, not carriers, as the most powerful and significant elements of naval power. Had the U.S. wanted to preserve its key assets from attack, it would almost certainly have focused on protecting battleships. It was the attack on Pearl Harbor itself that first helped vault the carrier ahead of the battleship in importance. The attack demonstrated the carrier's unprecedented ability to attack the enemy at a great distance, with great force and surprise. The U.S. would turn this ability against Japan. Elimination of battleships from the Pacific Fleet forced the Americans to rely on carriers for offensive operations. Lack of court-martial Another issue in the debate is the fact neither Admiral Kimmel nor General Short ever faced court martial. It is alleged this was to avoid disclosing information showing the U.S. had advanced knowledge of the attack. When asked, "Will historians know more later?", Kimmel replied, "' ... I'll tell you what I believe. I think that most of the incriminating records have been destroyed. ... I doubt if the truth will ever emerge.' ..." From Vice Admiral Libby, "I will go to my grave convinced that FDR ordered Pearl Harbor to let happen. He must have known." It is equally likely this was done to avoid disclosing the fact that Japanese codes were being read, given that there was a war on. Unreleased classified information Part of the controversy of the debate centers on the state of documents pertaining to the attack. There are some related to Pearl Harbor which have not yet been made public. Some may no longer exist, as many documents were destroyed early during the war due to fears of an impending Japanese invasion of Hawaii. Still