If Hitler took Poland then Britain and France would declare war on him, which they did.
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Britain France and the soviet union agreed to declare war against Hitler
No. Hitler had a Pact with the Soviet Union that split Poland between them. The invasion of Poland lead Britain and France to declare war on Germany. The Soviets entered the war when Hitler invaded Russia.
Poland
Stalin became his allie
Hitler declared war on the USA on 11 December 1941, during a Reichstag speech in Berlin.
the year 4000
Hitler threatened to declare war on Czechoslovakia because the Czech government declared martial law.
the Britain
James Madison asked Congress to declare war on Britain in 1812.
Great Britain declared war on Germany after Hitler invaded Poland. Poland was a member of the Allies, along with Britain and France, so that meant that the other allied nations would come to Poland's aid.