When people begin learning about Pearl Harbor in a more in-depth manner, their first question is often the same: why was Pearl Harbor attacked? We know Europe was fully engulfed in World War II at the time, so why did the Japanese decide to attack the US?

To better answer the question of why Pearl Harbor was attacked, let’s step back for a moment and follow the chain of events that led up to the terrible events of December 7, 1941.

The European War

Before the attack on Pearl Harbor, the world was anything but peaceful. On September 1, 1939, Germany’s leader, Adolph Hitler, invaded Poland. Though Germany had previously angered the British and French by annexing Austria and Hungary, this attack was the breaking point. They declared war, plunging the world into a conflict that would soon spread around the globe.

America was allied with Britain and France at the time, but many Americans were in favor of isolationism – meaning they wanted to stay out of all foreign conflicts. Although he wanted to support the Allies, President Franklin D. Roosevelt had a hard time convincing Congress and the American public that the US should go to war. Instead, he adopted the Lend-Lease Act in March 1941, which gave him virtually unlimited power to control money and supplies that would go to the European war effort.

These events don’t directly explain why Pearl Harbor was attacked, but they do provide context and explain how American service members did eventually land on foreign soil.

Tensions between the US and Japan

It’s hard to image the United States ever fighting with Japan, but before the attack, the two countries were very distrustful of one another.

We often think of 1939 as the start of war, but in reality, Japan’s declaration of war against China in 1937 (the beginning of the Second Sino-Japanese War) caused tensions to rise in the United States. The Japanese were increasingly cruel to their Chinese subjects. They committed a number of atrocities, including executing POWs without trials.

Rather than sending soldiers, the US decided to use economic sanctions against the Japanese to curtail their acts of aggression. They launched trade embargoes that denied the Japanese access to a variety of goods – including oil. The Japanese, however, were not moved. Instead, they vowed to stand even firmer.

Though leaders in Tokyo and Washington tried to find common ground, the US – Japanese relationship did not improve, and it seemed that war would be the only answer.

Why Pearl Harbor?

Very few military officials believed that the Japanese would launch a direct attack on American soil, especially in Hawaii. The naval base and Japan were 4,000 miles apart. These days, we might not think much of that distance, but back then, it was a long, difficult flight. American officials who were monitoring coded Japanese messages were certain that European colonies in Southeast Asia were more at risk than Pearl Harbor.

That belief, unfortunately, led to another major miscalculation. Because no one believed Pearl Harbor would be attacked, it was left mostly unguarded. Most of the Pacific Fleet was there on that fateful morning, a fact that seemed too good to be true for the Japanese.

Why was Pearl Harbor attacked?

USS Arizona’s magazine explodes

As it turned out, it was too good to be true. On December 8, 1941—the day after the attack—President Roosevelt declared war on Japan and her allies Germany and Italy, and the US began sending troops overseas, turning the tide of war in favor of the Allies at last

The day of the attack was without a doubt a “date which will live in infamy,” and hopefully now you have a better understanding of why Pearl Harbor was attacked, and you’ll be able to enjoy your tour just a bit more.

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