A. the japanese attack on pearl harbor
The answer is that it established the power of the federal government. It allowed state government to overule the federal government also established the power of state government. And decided the the federal government cannot tax states.
B. The English government forced them to leave.
It was because the Germans started the war and Germany is in Europe plus Germany's ally Italy was in Europe. So the allies had to focus in the big part of the war.
