No, it wasn't WWII that pulled us out of the depression, which started in the 20's. This is a very nice piece that was brought to my attention, called "Franklin Roosevelt's RFC: A Lesson for Today" (Video about 20 minutes).
And, no, FDR was not a communist, taking over the United States for Stalin. He repaired the hideous damage done by the speculators to the conditions of life in our country (as they're again doing today), and once the banks were up and running again, turning profits by loaning for productive purposes, they were re-privatized, having been partially purchased by the Federal Government to get the real banks through the crisis.
And it was because FDR used the sovereign credit of the United States to fund infrastructure as well as other projects and needs (like paying Chicago's teachers who hadn't been paid in nine months), that we had the industrial base again to defend the world from the Nazis.