Relations between the United States and Japan deteriorated significantly when Japan invaded China. Americans had consistently demonstrated sympathy for China, driven by their extensive history of missionary work and substantial trade relations. Notably, President Roosevelt acknowledged early in his presidency, revealing his sympathy for China due to his familial ties to the Delano family, who had engaged extensively in China’s trade.

Initially, the Japanese military achieved military success in China. However, by 1940, the Japanese appeared trapped in a stalemate. A new military government came to power in Japan with the dual objectives of breaking the military stalemate and reducing Japan’s dependence on the United States. Over the ensuing year, as Japan expanded its influence southward, the United States attempted to employ economic leverage against Japan. Initially, the U.S. imposed a ban on the export of high-octane aviation fuel to Japan. Subsequently, when Japan occupied Indo-China, the U.S. halted the export of petroleum, which Japan relied upon. This effectively made war inevitable unless a negotiated settlement could be reached.

By the conclusion of November, it became evident that no settlement could be achieved. Intercepted Japanese communications provided the United States with the knowledge that if a settlement were not finalized by November 29th, unforeseen events would render it impossible to reach a resolution. The pivotal event in this scenario was the commencement of the Japanese attack fleets’ deployment. The Japanese had devised a plan to simultaneously launch attacks on the Philippines, Singapore, Malaysia, and other targets. The centerpiece of this plan was an audacious assault on Pearl Harbor, the United States’ primary base in the Pacific. The objective was to ambush the American fleet while it was anchored.

The harbor in Pearl Harbor was deemed insufficiently deep for the effective utilization of torpedoes. However, the Japanese Navy had developed a torpedo capable of operating in shallow waters. The plan’s author was Isoroku Yamamoto, Commander of the Imperial Navy. Yamamoto, a Harvard graduate and former Japanese Naval attaché in Washington, harbored reservations about engaging in war with the United States. The Japanese Naval Commander held the belief that, despite potential initial victories, Japan could never surpass America’s industrial prowess. Despite his reservations, Yamamoto devised a campaign that would provide the Japanese with the optimal opportunity: delivering a decisive blow that would cripple the U.S. fleet. Six Japanese carriers, commanded by Vice Admiral Chuichi Nagumo, embarked on their journey towards Hawaii. At 6:10 AM, the Japanese carriers commenced the launch of their aircraft, comprising 183 fighters, bombers, dive-bombers, and torpedo planes, directed towards Oahu and Pearl Harbor. An hour later, the second wave of aircraft was launched. In total, 350 aircraft were dispatched towards the island.

Despite receiving warnings from Washington regarding the possibility of war, the U.S. forces made no specific preparations in Hawaii. The U.S. Navy assumed that the Army was responsible, while the Army believed that the Navy held command. Furthermore, no one anticipated a Japanese attack on Pearl Harbor. Consequently, not all the radar stations on the island were manned. The aircraft at the airbases were arranged in a parade formation, and the Navy’s battleships were neatly moored in Battleship Row. These factors rendered the U.S. forces vulnerable to the Japanese attack. The battleship U.S.S. Arizona was swiftly sunk when a bomb detonated in the forward magazine. The sinking of the Arizona entombed 1,103 American sailors, forever lost. Additionally, 17 ships were either crippled or sunk, resulting in a total of 2,403 servicemen losing their lives. 175 U.S. aircraft were destroyed. Fortunately for the Americans, the U.S. Carriers were out at sea during the attack. The Japanese decided to halt the assault after the second wave, sparing the critical fuel storage tanks and repair facilities at Pearl Harbor.

President Roosevelt was informed of the Japanese attack at 1:40 PM. By 3 PM, he was convening with his advisors to determine the necessary actions. The following day, following a cabinet meeting that evening, F.D.R. addressed Congress and requested a Declaration of War against Japan.