I've heard this but I don't really understand the premise. What was WWII but an enormous amount of government borrowing and spending, like the New Deal on steroids? The CCC hired men to build parks while the Army hired men to kill Germans. When the government orders millions of tanks and warplanes, which in economic terms might as well have been dumped in the ocean right off the assembly line, how is that not a stimulus package? I just don't get it.

This similar post may be of interest to you though I'm sure there's always room for further discussion.