A because Japan hated Hitler a lot and they did not get along
The final fall of the Byzantine Empire was caused by attacks from the Ottomans.
The Byzantine Empire fell, and Islam spread into Eastern Europe. The Byzantine Empire fell in 1453. The main reason of its fall was a significant number of attacks made by the Ottoman Turks. In 1454, Constantinople finally surrendered to them.
Answer:
I believe 2 reasons are:
1.) The U.S didn't know what Hitler was doing until after the war
2.) The U.S wasn't sure how destructive he would be
