In the early morning of Dec. 7, 1941, the U.S. naval base at Pearl Harbor, Hawaii, was attacked by the Japanese military. At the time, Japan's military leaders thought the attack would neutralize American forces, allowing Japan to dominate the Asia Pacific region. Instead, the deadly strike drew the U.S. into World War II, making it a truly global conflict. These are the most important facts that should be recalled about this historical event.

What Is Pearl Harbor?

Pearl Harbor is a natural deepwater naval port on the Hawaiian island of Oahu, located just west of Honolulu. At the time of the attack, Hawaii was an American territory, and the military base at Pearl Harbor was home to the U.S. Navy's Pacific Fleet.

U.S.-Japan Relations

Japan had embarked on an aggressive campaign of military expansion in Asia, beginning with its invasion of Manchuria (modern-day Korea) in 1931. As the decade progressed, the Japanese military pushed into China and French Indochina (Vietnam) and rapidly built up its armed forces. By the summer of 1941, the U.S. had cut off most trade with Japan to protest that nation's belligerence, and diplomatic relations between the two nations were very tense. Negotiations that November between the U.S. and Japan went nowhere.

Lead-Up to the Attack

The Japanese military began laying plans to attack Pearl Harbor as early as January 1941. Although it was Japanese Admiral Isoroku Yamamoto who initiated the plans for the attack on Pearl Harbor, Commander Minoru Genda was the plan's chief architect. The Japanese used the code name "Operation Hawaii" for the attack. This later changed to "Operation Z."

Six aircraft carriers left Japan for Hawaii on Nov. 26, carrying a total of 408 fighter craft, joining five midget submarines that had departed a day earlier. Japan's military planners specifically chose to attack on a Sunday because they believed Americans would be more relaxed and thus less alert on a weekend. In the hours before the attack, the Japanese attack force stationed itself approximately 230 miles north of Oahu.

The Japanese Strike

At 7:55 a.m. on Sunday, Dec. 7, the first wave of Japanese fighter planes struck; the second wave of attackers would come 45 minutes later. In a little under two hours, 2,335 U.S. servicemen were killed and 1,143 were wounded. Sixty-eight civilians were also killed and 35 were wounded. The Japanese lost 65 men, with an additional soldier being captured.

The Japanese had two major objectives: Sink America's aircraft carriers and destroy its fleet of fighter planes. By chance, all three U.S. aircraft carriers were out to sea. Instead, the Japanese focused on the Navy's eight battleships at Pearl Harbor, all of which were named after American states: Arizona, California, Maryland, Nevada, Oklahoma, Pennsylvania, Tennessee, and West Virginia.

Japan also targeted nearby Army airfields at Hickam Field, Wheeler Field, Bellows Field, Ewa Field, Schoefield Barracks, and Kaneohe Naval Air Station. Many of the U.S. airplanes were lined up outside, along with the airstrips, wingtip to wingtip, in order to avoid sabotage. Unfortunately, that made them easy targets for the Japanese attackers.

Caught unawares, U.S. troops and commanders scrambled to get planes in the air and ships out of the harbor, but they were able to muster only a feeble defense, largely from the ground.

The Aftermath

All eight U.S. battleships were either sunk or damaged during the attack. Amazingly, all but two (the USS Arizona and the USS Oklahoma) were eventually able to return to active duty. The USS Arizona exploded when a bomb breached its forward magazine (the ammunition room). Approximately 1,100 U.S. servicemen died on board. After being torpedoed, the USS Oklahoma listed so badly that it turned upside down.

During the attack, the USS Nevada left its berth in Battleship Row and tried to make it to the harbor entrance. After being repeatedly attacked on its way, the USS Nevada beached itself. To aid their airplanes, the Japanese sent in five midget subs to help target the battleships. The Americans sunk four of the midget subs and captured the fifth. In all, nearly 20 American naval vessels and about 300 aircraft were damaged or destroyed in the attack.

The U.S. Declares War

The day following the attack on Pearl Harbor, U.S. President Franklin D. Roosevelt addressed a joint session of Congress, seeking a declaration of war against Japan. In what would become one of his most memorable speeches, Roosevelt declared that Dec. 7, 1941, would be "a date that will live in infamy." Only one legislator, Rep. Jeanette Rankin of Montana, voted against the declaration of war. On Dec. 8, Japan officially declared war against the U.S., and three days later, Germany followed suit. World War II had begun.