Japan’s war planners, specifically Admiral Isoroku Yamamoto, never gave any thought the galvanizing effect a surprise attack might have on the American public. Since the war it has been a source of debate among historians what would have happened if Japanese diplomats Saburō Kurusu and Kichisaburō Nomura had delivered the declaration of war on time. It is unlikely a timely delivery would have much effect in preventing the United States from crying out for blood with only a half-hour warning. Curiously the psychological effect of such an attack was never considered. But the Japanese were upset that the declaration was delivered after the attack started.
The Pearl Harbor attack was just part of an orchestrated, Pacific-wide assault. Seriously underestimating the naval, air, and ground strength of Japan, the Allies assumed that they would be able to ward off blows that would come in succession. They did not expect the Japanese to attack all predicted targets at the same time. As casualties and losses mounted, it would have been unlikely that the United States would have responded any other way than total war.
United States President Franklin D. Roosevelt, declaring war on December 8, 1941, declared the previous day a “date that will live in infamy,” and listed all of the places in the Pacific that the Japanese attacked. Still, the serious condition of the US Pacific Fleet was kept a secret, partly out of the desire to not panic the public, especially the west coast. Also, the War Department did not wish to give information to the enemy, which they assumed was reading American papers. A serious crisis had befallen the Americans.
Should they begin to pull back the buildup on the Atlantic? Roosevelt, who wanted war with Germany, particularly worried that the European war, a far greater threat in his estimation, would be seen in the United States as a European problem and Japan as the Americans' sole concern. Within days, Reichskanzler Adolf Hitler would alleviate his concerns.
In Berlin on December 8, 1941, Adolf Hitler was elated. “We have ally that has not been defeated in 1500 years!” he told Minister of Propaganda Josef Goebbels. On December 11, 1941, Hitler gave a speech to the Reichstag. Confused and rambling, he compared his own childhood of poverty to that of the wealthy Roosevelt. He then declared war on the United States.
In doing so, he ensured his own destruction. United Kingdom Prime Minster Winston Churchill, when he heard of Pearl Harbor, remarked, “so we have won after all!” The American public would have been quite content with dealing with Japan and leaving the European War to the Europeans. The treachery of the Japanese attack burned bright in the minds of most Americans, and they wanted revenge. If not for the declaration of war by Germany, Roosevelt would have had a hard time justifying declaring war on Germany until Japan was destroyed. But Germany did declare war, and the U-boats moved the Eastern seaboard in January 1942.
The United States was completely unprepared for the U-boat war that was about to descend on it. While the Neutrality Patrol had ensured safe passage of merchant ships bound for England under US Navy protection, she did not have enough escorts for her own waters. Also, the U-boats operated far from the coast of the United States. Her inland merchant fleet saw no need to adopt the measures the British suggested. Convoys, coastal blackouts, watch stations, and other precautions were ignored.
The result was a slaughter. The U-boat commanders called it Operation Drumbeat — Paukenschlag — and very little was available to stop them. Yachtsmen used to plying the calm summer waters of the coast were sent far out into the Atlantic in winter, facing a greater threat from the weather than of combat.
The United States did not sink a single U-boat operating off the United States or the Mediterranean until March 1, 1942, when a US Navy PBO Ventura sank U-656 off Newfoundland. It had taken three months for the Americans to make their first kill. For the Germans it was a second “happy time.”
US Navy Admiral Ernest J. King, who obsessed about the war in the Pacific, did not recognize the importance of convoys until it was too late. A blackout of coastal cities was not ordered, allowing U-boats to use the city skylines to illuminate the outlines of ships. Residents of beachfront towns would watch the burning ships offshore at night and discover dead sailors washed up on the beach the next day.
The United States Coast Guard, now part of the Navy, stepped up patrols and the building of antisubmarine escorts. The Navy pressed blimps into service to supplement long-range aircraft. But the US Army Air Corps and the US Navy argued, like RAF Coastal Command and RAF Bomber Command before them, about allocating lone-range aircraft to strategic missions or for antisubmarine patrols.
The destruction was greater than that at Pearl Harbor, and despite the secrecy of the losses, the American people began to accept that they would have to fight Germany as well. The war right offshore could not be hidden completely form the public.
The war in Europe was secured in the mind of the American public with a propaganda series called Why We Fight. In it, Hollywood director Frank Capra outlined the rise of Nazism and the reasons why England and France went to war. Powerful in its simplicity, Capra used footage from Nazi propaganda films to great effect. Roosevelt ordered the series, originally made for the Armed Forces, to be shown in movie theatres across the United States. By the end of 1942, the was no question that the United States' war with Nazi Germany was necessary.