In 1776, the Thirteen Colonies declared their independence from Britain. With the help of France and Spain, they defeated the British in the American Revolutionary War. In the Treaty of Paris (1783), Britain officially recognized the independence of the United States of America.
The immediate cause was Germany invading Poland on September 1, 1939, and Britain and France declaring war on Germany on September 3, 1939. Problems arose in Weimar Germany that experienced strong currents of revanchism after the Treaty of Versailles that concluded its defeat in World War I in 1918.
Canefight! Preston Brooks and Charles Sumner!