"The Open Door Policy was a policy between China, the US, Japan, and several European powers that stated each of those countries should have equal access to Chinese trade."
FDR was a progressive Democrat who firmly believed in the power of a strong Central government to solve the problems of the day.
This differed from Coolidge and Hoover who believed in the power of business to solve problems and saw a limited role for government.
A.
The Americans were able to find out about the planned attack the Japanese were plotting; and were able to counter it.
The Japanese got most of their navy whipped.