The United States
The Attack on Pearl Harbor marked a surprise military strike perpetrated by the Imperial Japanese Navy Air Service upon the United States attacking the naval base at Pearl Harbor in Honolulu, Hawaii on Sunday morning, December 7, 1941. As a result of this attack, the United States enters into World War II the next day.
Lincoln hoped to use a well-known figure of speech to help rouse the people to recognition of the magnitude of the ongoing debates over the legality of slavery. His use of this paraphrased metaphor is perhaps clearer when you look at some more of his speech:
"A house divided against itself cannot stand." I believe the government cannot endure permanently half slave and half free. I do not expect the Union to be dissolved — I do not expect the house to fall — but I do expect it will cease to be divided. It will become all one thing or all the other. Either the opponents of slavery will arrest the further spread of it, and place it where the public mind shall rest in the belief that it is in the course of ultimate extinction; or its advocates will push it forward till it shall become alike lawful in all the States, old as well as new — North as well as South.
As you can see, in this metaphor, the "house" refers to the Union — to the United States of America — and that house was divided between the opponents and advocates of slavery. Lincoln felt that the ideals of freedom for all and the institution of slavery could not coexist — morally, socially, or legally — under one nation. Slavery must ultimately be universally accepted or universally denied.
Hitler capitalized on economic woes, popular discontent and political infighting to take absolute power in Germany beginning in 1933. Germany's invasion of Poland in 1939 led to the outbreak of World War II, and by 1941 Nazi forces had occupied much of Europe.