The United States spent the first years of World War II keeping its military out of the conflict. Though it lent aid to the British, it refused to outright join and declare war on any of the Axis powers. From 1939 to 1941, the nation was able to maintain its isolationism. Then came December 7, 1941, a dark day in American history. What was America’s response to Pearl Harbor?

Response to Pearl Harbor

Battleship Row, Pearl Harbor December 7, 1941

In the quiet of a tropical Sunday morning, a Japanese aerial striking force flew over the island of Oahu, part of the American Territory of Hawaii, and launched a surprise assault on multiple military installations. Airfields were devastated, their aircraft destroyed to prevent a counter-strike, but the majority of the damage was centered around Pearl Harbor, the naval base on the southern part of the island.

Eight battleships of the US Pacific Fleet were present at Pearl Harbor that morning, and it was Japan’s intention to destroy each of them. The purpose? To keep the Americans from meddling in the conflict taking place more than 3,000 miles across the Pacific. The attack on Pearl Harbor left more than 2,400 Americans dead and shocked the nation, sending shockwaves of fear and anger from the West Coast to the East.

The following day, President Franklin D. Roosevelt addressed Congress, asking them to declare war on Japan, which the did by an almost-unanimous vote. But perhaps surprisingly, the nation’s first response to Pearl Harbor wasn’t made in the Pacific.

Picking a Front

That move was made across the Atlantic, in the European Theater. The reason for this was that in response to the American declaration of war on Japan, Germany and Italy declared war on the United States. The shock of the Japanese attack was still fresh in the minds of the American public when Congress was forced to reply to the German and Italian declarations by also declaring war on them.

With a war on two fronts, Congress and Roosevelt were forced to decide what the first move would be. How would the United States, a nation that never wanted to join World War II, deal with both the Pacific and European fronts? Would it be a matter of dealing with both the Japanese and the Germans at the same time? Would one need to be the focus before the other could be made a priority?

German troops parade through Warsaw, Poland September 1939

While the nation may have assumed Japan was going to be the priority, there were two major differences between the Pacific and European theaters. Adolph Hitler’s forces had captured considerable territory in Europe, which posed a greater immediate threat to the world than Japan’s conquest of Asian territories. With much of Europe and the Atlantic under Nazi control, the United States was at risk of being the next target.

Compared to Japan, Germany was also far more militarily advanced. German scientists and engineers worked tirelessly to develop dangerous weapons of war and one of Roosevelt’s prime concerns was the nation’s creation of unmatched weaponry. An atomic bomb was a very real concern that would have proven devastating to the world if placed in Hitler’s hands.

If those concerns weren’t enough, the United States had been urged by the United Kingdom to join the war against the Axis from the beginning the conflict. Even if the US had intended to assist the Chinese first, the British were considered better equipped to put up a fight against Germany. Across the Pacific, China’s military was considerably weaker than Japan’s and wouldn’t be able to lend much help in the war in the Pacific. For the most part, it would land on the US Navy to take on the Japanese in the Pacific. Prime Minister Winston Churchill worked closely with Roosevelt on a “Germany First” war strategy, hoping to prevent the United States from having to divide resources between Europe and the Pacific.

Though it would seem to make sense to try and strike Japan early on, and prevent them from taking territories across the Pacific, Hitler, and the urging from Churchill, made Roosevelt’s decision easier. By attacking the Soviet Union, Germany’s forces were suddenly fighting a war on two fronts. With their focus divided between east and west, it made strategic sense to try and knock Germany out of the war first.

When Did the United States Make a Move Against Japan?

Response to Pearl Harbor

The US wanted revenge against Japan

Though the US military initially assisted Churchill and Britain in Europe, that didn’t mean that no action was taken in the Pacific in response to Pearl Harbor. While Churchill may have been able to shift Roosevelt’s attention to Europe, Americans still called for revenge on the nation that attacked their territory.

Early on, the United States took more defensive measures, setting up command in Brisbane, Australia after losing the Philippines. The presence of American military in Australia was intended to prepare for a counter-offensive against Japan’s perimeter, centered on the port of Rabaul in New Guinea.

At the Arcadia Conference, where Churchill presented Roosevelt and American military leaders with the “Germany First’ strategy, the British Prime Minister, and the US military came to an understanding that the majority of American military resources would initially go to Europe. Admiral Ernest J. King, the newly-appointed Commander of Naval Operations, was less pleased with a defensive stance toward Japan, and fought to have wording included that allowed the seizure of “vantage points” to develop a counter-offensive.

While the Army prepared to bring resources to Europe, King and the Navy set their sights on the Pacific. In early 1942, the two branches of military debated over the allocation of troops. As Japan’s aggression toward Australia started to grow, Roosevelt, who was at first on board with the “Germany First” stance, started to side with Admiral King’s more aggressive Pacific strategy. By April of 1942, the Pacific War Campaign Plan was created as an outline for the conflict with Japan.

Though Roosevelt would end up going back and forth on the “Germany First” policy, King had already routed the American aircraft carriers to the Pacific, a sign that war in the Pacific was gaining momentum. As a symbol of American resolve and to show that Japan wasn’t invincible, the United States launched the Doolittle Raid against Tokyo in April of 1942. Though the raid caused little damage, it was the morale boost the United States needed as the war in the Pacific started to pick up steam.

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