Who had the greatest impact on ending the Great Depression during Franklin Roosevelt's presidency ?

Certainly some of the credit for ameliorating the effects of the Depression, as well as constructing a regulatory apparatus to manage the American economy to minimize the risk of further depressions, must belong to Roosevelt himself. His New Deal was the most significant package of legislation passed in American history, completely altering the relationship between the federal government, the economy, and the American people themselves. On the other hand, the people who did the most to bring about the end of the Depression were the leaders of the Axis nations who started the Second World War. It was the outbreak of this conflict, and not the New Deal, that brought about the end of the Great Depression in the United States. In 1938, the American economy still faced high unemployment and stagnant economic growth, the results of the "Roosevelt recession" that commenced when FDR rolled back spending on many New Deal programs. By 1940, however, the United States was in the process of mobilizing for war, spending billions on military preparation, and unemployment neared record lows. Even before Pearl Harbor, the United States had become what FDR termed the "arsenal of democracy," supplying the British in particular with war materiel and funds to sustain its fight against the Nazi war machine. It was this tragic event that shocked the American economy out of the Great Depression.