That was when the Japanese bombed Pearl Harbor and we were at war with Japan; the Great Depression happened before that: from around 1929 to just about 1941 and was deepened in 1936 as we were slowly recovering when FDR instituted policies that destroyed business/jobs and investing. For a great book on it all read: FDR’s Folly - How Roosevelt and His New Deal Prolonged the Great Depression by Jim Powell.
Bkmk for later read.