Japan attacked China in 1937, and its military forces were guilty of increasingly hideous brutality, culminating in the “Nanking Massacre” of December 1937. Even German observers, no strangers to evil, were shocked as Japanese soldiers committed countless brutal rapes, bayonetted or decapitated up to 40 thousand Chinese prisioners or war, and engaged in other senseless acts of barbarity. As news of this horror spread around the world, pressure mounted on political leaders to do something.

Japan had few natural resources on its home islands and was very dependent on imports of metals and oil to feed its war machine. The United States was its chief supplier. President Roosevelt began restricting exports to Japan, starting with scrap iron and culminating with an embargo on oil shipments on August 1, 1941, shortly after the Japanese occupied French Indo-China. Without new sources of oil Japanese reserves would soon be depleted, and their military campaigns would need to be suspended. Oil could be acquired by taking the Dutch East Indies, but a move against the Dutch would undoubtedly bring the British into the war and probably involve the United States.

The Japanese attempted to persuade the United States to resume oil shipments, but when it became apparent this effort would fail, they decided on war. To prevent America from interfering with its plan to move south against the Dutch oil fields, Japan embarked on a bold effort to cripple the American Pacific Fleet — thus the surprise attack on Pearl Harbor.

The December 7 attack on America’s Hawaiian naval base was masterfully executed, and it resulted in the destruction or serious damage to all of the Pacific fleet’s battleships and many aircraft. It took months for our navy to recover. Nevertheless, it was a tactical failure and a strategic disaster. Tactically, it failed to destroy any American carrier, all of which were out of harbor. Also, the American oil tanks and ship-repair facilities were not hit. Strategically, it enraged and united a previously divided Amerecan citizenry, now fixated on Japan’s destruction.