The causes of the Economic Boom of the 1920s were the Republican government's policies of Isolationism and Protectionism, the Mellon Plan, the Assembly line and the mass production of consumer goods such as the Ford Model T Automobile and luxury labor saving devices and access to easy credit on installment plans.
Answer: A) Herbert Hoover
Herbert Hoover began his service as President of the United States in 1929. He was in office when the Great Depression began, and was blamed for the fact that the country struggled as it did. The problems that led to the Depression had been building up for years before Hoover took office, but as the leader of the country when the troubles hit, he was the one who took the bulk of the criticism. And Hoover really had no solutions to the problems. In the 1932 presidential election, he was defeated by Franklin D. Roosevelt. Roosevelt implemented "New Deal" policies to combat the Depression.
To not interfer with our hemisphere or they would face trade issues