MT,
It didn't work then because the depression was world wide. As a result of the post-war depression in Western Europe during the 1920s, foreign markets for American products began to dry up. This, along with overproduction, led to massive layoffs in U.S. factories, which was one of the major factors leading to the onset of the Great Depression in the U.S. While Hoover's administration received much of the blame for this, there was little anyone could have done to prevent it, given the reality of the economic conditions overseas. The same foreign economic forces continued to place a drag on the U.S. economy throughout the 1930s, effectively dampening any benefit that might have been derived from Roosevelt's New Deal and "prime the pump" policies. As you know, the Second World War ended the Depression with massive Government spending and full-employment. Indeed, one might make the point that it was the war-time "prime the pump" spending that reversed the country's economic fortunes. The U.S. emerged from the war as practically the only western democracy with a strong, intact economy.
Regards, Shuckins