Japanese war crimes
The U.S. officially classified all 3,649 military and civilian casualties and destruction of military property at Pearl Harbor as non-combatants as there was no state of war between the U.S. and Japan when the attack occurred. Joseph B. Keenan, the chief prosecutor in the Tokyo Trials, says that the attack on Pearl Harbor not only happened without a declaration of war but was also a treacherous and deceitful act. In fact, Japan and the U.S. were still negotiating for a possible peace agreement which kept U.S. officials very distracted when Japanese planes bombed Pearl Harbor. Keenan explained the definition of a war of aggression and the criminality of the attack on Pearl Harbor:
Pearl Harbor
Following the overthrow of the Hawaiian Kingdom, the United States Navy established a base on the island in 1899. On December 7, 1941, the base was attacked by the Imperial Japanese Navy airplanes and midget submarines, causing the American entry into World War II. One of the main reasons that Pearl Harbor happened was because the United States had major communication breakdowns among several branches of the U.S. armed services and departments of the U.S. government. This led to the surprise Japanese attack at the Hawaiian air base. There was no meaningful plan for the air defense of Hawaii, for American commanders had no understanding of the capabilities and proper employment of air power. As it was, had the Pacific Fleet acted on the war warnings it undoubtedly would have sortied and been at sea on December 7, where the major ships would have been sunk in deep water, making salvage impossible. 
Shortly after the devastating Japanese surprise attack at Pearl Harbor two American military commanders, Lt. Gen. Walter Short and Adm. Husband Kimmel were demoted of their full ranks. The two American commanders later sought to restore their reputations and full ranks.