Editing Axis powers (section)

==German, Italian and Japanese World War II cooperation==
===German–Japanese Axis-cooperation===
{{Main|Germany–Japan relations#Rapprochement, Axis and World War II (1920–1945)}}
{{See also|Germany–Japan industrial co-operation before World War II}}

On 7 December 1941, Japan [[attack on Pearl Harbor|attacked the US naval bases in Pearl Harbor]], Hawaii. According to the stipulation of the [[Tripartite Pact]], Nazi Germany and Fascist Italy were required to come to the defense of their allies only if they were attacked. Since Japan had made the first move, Germany and Italy were not obliged to aid her until the United States counterattacked. Nevertheless, expecting the US to declare war on Germany in any event,<ref>Kershaw, Ian. Fateful Choices: Ten Decisions the Changed the World, 1940–1941 New York: Penguin, 2007. pp. 444–446 {{ISBN|978-1-59420-123-3}}</ref> Hitler ordered the ''[[Reichstag (Weimar Republic)|Reichstag]]'' to [[German declaration of war against the United States (1941)|formally declare war on the United States]].{{sfn|Kershaw|2007|p=385}} Hitler had agreed that Germany would almost certainly declare war when the Japanese first informed him of their intention to go to war with the United States on 17 November 1941.<ref>Longerich, Peter ''Hitler: A Life'' (2019) p. 784</ref> Italy also [[Italian declaration of war on the United States (1941)|declared war on the US]].

Historian [[Ian Kershaw]] suggests that this declaration of war against the United States was a serious blunder made by Germany and Italy, as it allowed the United States to join the war in Europe and North Africa without any limitation.{{sfn|Kershaw|2007|loc=Chapter 10}} On the other hand, American destroyers escorting convoys had been effectively intervening in the [[Battle of the Atlantic]] with German and Italian ships and submarines, and the immediate war declaration made the [[Second Happy Time]] possible for U-boats.<ref>{{cite book |author1=Duncan Redford |author2=Philip D. Grove |title=The Royal Navy: A History Since 1900 |url=https://books.google.com/books?id=U6FrAwAAQBAJ&pg=PA182 |year=2014 |publisher=I.B. Tauris |page=182|isbn=9780857735072 }}</ref> Franklin D. Roosevelt had said in his Fireside Chat on 9 December 1941, 2 days before the European Axis powers formally declared war on America, that Germany and Italy already considered themselves to be in a state of war with the United States.<ref>{{cite web|url=http://www.presidency.ucsb.edu/ws/?pid=16056|title=Franklin D. Roosevelt: Fireside Chat.|website=www.presidency.ucsb.edu}}</ref> Plans for [[Rainbow Five]] had been published by the press early in December 1941,<ref>{{cite web|url=http://www.upi.com/Archives/1987/12/02/Historian-FDR-probably-engineered-famous-WWII-plans-leak/4189565419600/|title=Historian: FDR probably engineered famous WWII plans leak |publisher=upi.com}}</ref> and Hitler could no longer ignore the amount of economic and military aid the US was giving Britain and the USSR.<ref>{{cite news |url=http://news.bbc.co.uk/onthisday/hi/dates/stories/december/11/newsid_3532000/3532401.stm|title=BBC On This Day – 11 – 1941: Germany and Italy declare war on US |website=BBC News |date=11 December 1941 |publisher=BBC}}</ref>

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File:Bundesarchiv Bild 183-1987-0703-507, Berlin, Reichstagssitzung, Rede Adolf Hitler.jpg|[[s:Adolf Hitler's Declaration of War against the United States|Hitler declaring war on the United States]] on 11 December 1941
File:Savoia-Marchetti SM.75 GA RT in East Asia.jpg|Italian pilots of a [[Savoia-Marchetti SM.75]] long-range cargo aircraft meeting with Japanese officials upon arriving in East Asia in 1942
File:German and Japanese spheres of influence at greatest extent World War II 1942.jpg|German and Japanese direct spheres of influence at their greatest extents in Autumn 1942. Arrows show planned movements to an agreed demarcation line at 70° E, which was, however, never approximated.
</gallery>