Nazi Germany declared war against the United States on December 11, 1941, four days after the Japanese attack on Pearl Harbor and three days after the United States declared war on Japan. German officials said they were responding to a "series of provocations" by the United States when it was still officially neutral during World War II. Adolf Hitler made the decision after two days of consultation with Goring, Keitel, Raeder and German Foreign Minister Joachim von Ribbentrop, all of whom advised him to immediately declare war in view of the publication of the secret U.S. war plan Rainbow Five, and so the Kriegsmarine could begin the Second Happy Time. It has been referred to as Hitler's "most puzzling" decision of World War II.Kershaw (2007), p.382
The formal declaration was made by Ribbentrop in his office to American Leland B. Morris. That same day, Benito Mussolini announced Italy's declaration of war on the United States the U.S. declared war on Germany. Germany's declaration eliminated any remaining meaningful domestic isolationist opposition to the U.S. joining the European war.
Background
The course of relations between Germany and the United States had deteriorated since the beginning of World War II, largely because of the increasing cooperation between the United States and the United Kingdom. The Destroyers for Bases Agreement, Lend-Lease, the Atlantic Charter, the hand-over of military control of Iceland from the United Kingdom to the United States, the extension of the Pan-American Security Zone, and many other results of the special relationship which had developed between the two countries had put a strain on relations between the United States, still technically a neutral country, and Germany. United States warships escorting American supply vessels bound for the United Kingdom bearing aid were already engaged in an undeclared war with German U-boats.Bullock (1992), pp.766-67 Roosevelt's desire to help the British, despite the objections of the influential American isolationist lobby, and the Neutrality Acts imposed by Congress which prevented direct involvement in the war, brought the U.S. to push hard against the traditional boundaries of neutrality to prevent the Axis domination of Europe. By 1941, much of the Neutrality Acts had largely been repealed by the Lend-Lease Act, allowing Roosevelt more freedom to pursue further aid for Britain without legal impediments. Even before the Battle of France in 1940, American public opinion towards Germany had become increasingly hostile, particularly after Roosevelt won another election term in 1940.
On 7 December 1941, Japanese forces launched a surprise attack on the United States Pacific Fleet based at Pearl Harbor, Hawaii, heralding a war between Japan and the United States. Japan had not informed its ally, Germany, in advance of the attack, although the Japanese ambassador had communicated to the German Foreign Minister, Joachim von Ribbentrop, at the beginning of December that relations between the United States and the Japanese Empire had deteriorated to a point where hostilities were imminent. He was thereafter instructed to ask Germany for a commitment to declare war under the terms of the Tripartite Pact should that occur. Hitler and Ribbentrop had been urging Japan to attack and seize Singapore from the British, believing that doing so would not only harm the British cause, but would also serve to help keep the U.S. out of the war.Bullock (1992), pp. 661–664 Japanese leaders, including Hideki Tojo, were concerned that an attack on the United States would cause Germany to side with their racial kin and participate in an encircling of Japan with the United States and Britain. Therefore, the Japanese side urged for confirmation of German and Italian allegiance with Japan. On 28 November 1941, Ribbentrop confirmed to Hiroshi Ōshima, the Japanese ambassador to Germany, what Hitler himself had told Japanese foreign minister Yōsuke Matsuoka: that if Japan became embroiled in a war with the United States, Germany would, naturally, enter the war on Japan's side. When the Japanese asked for a written assurance of this, Hitler complied, with express consent from Mussolini. This agreement, drafted on 4 December, committed the primary Axis powers to go to war with the United States in the event of hostilities with Japan, and essentially superseded the Tripartite Pact as an offensive, rather than defensive, alliance.
According to the terms of their agreements, Germany was obliged to come to the aid of Japan if a third country attacked Japan, but not if Japan attacked a third country. Ribbentrop reminded Hitler of this, and noted that a declaration of war against the United States would add to the number of enemies Germany was fighting, but Hitler dismissed this concern as not being essential to the outcome of the war, and, almost entirely without consultation, declared war against the United States. Hitler sought to preempt what he believed was an imminent declaration of war by Roosevelt, even though Roosevelt had not planned to declare war on Germany.Kershaw (2007), pp.444–446 In general, the Nazi hierarchy held low regard for the military resolve of the U.S. under Roosevelt, a stance that is widely considered a major error in their strategic thinking. In their eyes the United States was a corrupt, decadent, Jewish-dominated nation weakened by its large populations of African Americans, immigrants, and Jewish-Americans.Table Talk, ed. Martin Bormann (1953). Remarks of 7 January 1942
American public opinion swung heavily against Germany after Pearl Harbor, which was believed to be inspired by or organized by Germany. A 10 December Gallup poll (after Pearl Harbor but before the German declaration of war) found that 90% of Americans answered "Yes" to the question "Should President Roosevelt have asked Congress to declare war on Germany, as well as on Japan?"Cantril, Hadley. "Public Opinion: 1935-1946". p. 1173.Norpoth, Helmut. "Unsurpassed: The Popular Appeal of Franklin Roosevelt". p. 39.Hill, Richard F. "Hitler Attacks Pearl Harbor: Why the United States Declared War on Germany". p. 37.
German declaration Hitler arrived in Berlin on Tuesday 9 December and met with Goebbels at midday, when he disclosed his intention to declare war in a speech to the Reichstag, postponing the declaration for 24 hours to give himself time to prepare.Mawdsley 2011, p. 221 A further meeting with Goebbels on 10 December finalised the planning, although Hitler had yet to work on his speech. The time selected was 3:00 pm, as it was a convenient time for German radio listeners and the broadcast could be received in Tokyo at 10:00 pm and in Washington DC at 8:00 am. Ribbentrop telephoned the German ambassador in Rome, asking him to contact Mussolini and ensure that Italy's declaration of war be coordinated with that of Germany. Meanwhile, there was considerable diplomatic activity to ensure that the amendments to the Tripartite Pact requested by the Japanese government be concluded; the Germans requested that the Japanese ambassador, Hiroshi Ōshima, should be empowered to sign the "No separate peace" clause on Tokyo's behalf to save time.Mawdsley 2011, p. 236
Britain and the United States were already aware of German intentions through Magic signals intelligence and on 9 December, Roosevelt gave one of his national "fireside chat" broadcasts in which he said the American people should "Remember always that Germany and Italy, regardless of any formal declaration of war, consider themselves at war with the United States at this moment just as much as they consider themselves at war with Britain or Russia".Mawdsley 2011, pp. 223–225 Churchill spoke in the House of Commons on the morning of 11 December, saying that "Not only the British Empire now but the United States are fighting for life; Russia is fighting for life, and China is fighting for life. Behind these four great combatant communities are ranged all the free spirit and hopes of all the conquered countries in Europe ... It would indeed bring shame upon our generation if we did not teach them a lesson which will not be forgotten in the records of a thousand years".Mawdsley 2011, p. 247
On Thursday 11 December 1941, American Leland B. Morris, the highest ranking American diplomat in Germany, was summoned to Foreign Minister Joachim von Ribbentrop's office where Ribbentrop read Morris the formal declaration; the meeting lasted from 2:18 to 2:21 pm.p. 247 The text was:
According to George F. Kennan, a diplomat who worked with Morris, after reading the declaration, Ribbentrop screamed at Morris, ("Your President has wanted this war, now he has it"), turned on his heels and left the room.Keenan, George F. (2020) Memoirs 1925-1950. p.96. . Plunkett Lake Press.The essence of Ribbentrop's comment to Morris, without the descriptive commentary, is confirmed by Bloch, Michael (1992) Ribbentrop: A Biography. New York: Crown. p.347 , citing Documents on German Foreign Policy - Series D - Volume XIII - June 23 - December 11 1941 (1945) pp.1004–1005. United States Government Printing Office, Telegram No. 577 (11 December 1941) from "Schmidt"
The same text had been sent to Hans Thomsen, the German in Washington, with instructions to present it to Cordell Hull, the United States Secretary of State, at 3:30 pm, German summer time, 8:30 am Eastern Standard Time.Smyth & Lambert 1964, p. 999 On their arrival however, Hull refused to see the German delegation and it was not until 9:30 that they were able to pass their note to Ray Atherton, the head of the Division of European Affairs.Mawdsley 2011, p. 253 In Berlin, there was consternation that Mussolini had decided to preempt Hitler and declare war in a speech from the balcony at the Palazzo Venezia at 2:45 pm; an estimated crowd of 100,000 gathered to hear his speech which lasted only four minutes.Mawdsley 2011, pp. 248-249
At 3:00 pm, Hitler addressed the 855 deputies of the Reichstag gathered in the Kroll Opera House, with a speech lasting for 88 minutes in which he listed German successes to date. The second part of the speech was devoted to an attack on Roosevelt and "the Anglo-Saxon Jewish-capitalist world", concluding that "In the 2,000 years of German history known to us, our has never been more unified and united than it is today".Mawdsley 2011, pp. 250–253 On the same day, German ambassadors in the capitals of the other Tripartite Pact signatories; Hungary, Romania, Bulgaria, Croatia and Slovakia, were instructed to obtain their declarations of war against the United States.
Roosevelt had written a brief note to Congress on the morning of 11 December asking them to declare war on Germany and Italy; meeting at noon, the motion passed through both houses without dissent, although there were some abstentions. Vice President Henry Wallace arrived at the White House with the declaration, which was signed by Roosevelt at 3:00 pm.Mawdsley 2011, pp. 253–254
Post-declaration opinions
According to Hitler's naval adjutant, Admiral Karl-Jesko von Puttkamer, the Japanese attack on Pearl Harbor actually buoyed Hitler's assurance in winning the war, and improved morale among the high leadership of the armed forces. Peter Padfield writes: