My older daughter is studying the Great Depression in her history class. She's in fourth grade, so obviously she and her class are only getting a cursory treatment of the period. Her study materials (as you can see here) generally state that Roosevelt's New Deal programs helped alleviate the Depression, although "some say" the Depression didn't really end until the United States entered World War II and industrial production ramped up to meet the country's military needs.
I'm not an economist so I have nothing to add to that debate; it's been going on for years and it's a conservative mantra that the New Deal failed and it was World War II that ended the Great Depression. I'm reminded of Paul Krugman's assertions that the Roosevelt's stimulus wasn't big enough to end the Depression, although he adds that the package wasn't nearly as big as Roosevelt wanted because he ran into fierce political opposition. Krugman makes this point because he believes that we need a much bigger stimulus package than we currently have, although he doubts that will be possible due to the opposition President Obama encountered to the first stimulus package. Krugman concisely summarizes his positions in the video interview posted here.
Getting back to the conservative belief that the New Deal failed and that World War II ended the Depression: They insist on this point because they believe that government spending is ineffective at providing economic stimulus. But, to paint World War II in the broadest possible way with the crudest possible brush, what was it besides a massive government spending program*? They make it sound like the war was some beneficent angel that appeared in our hour of need to render unto us a boon. But someone had to pay for all those tanks, planes, jeeps and liberty ships, and it wasn't the private sector. That was all government money. The people building them might not have been government employees but they might as well have been.
I've written before about the conservative movement's belief that any government spending is considered wasteful unless it's spending on the military. I don't think this will change any time soon. But it might be helpful to appeal to relatively sane majority of the population by framing any future stimulus package and even health care reform as "war" spending. The United States was in grave mortal peril during World War II. I believe it is in grave mortal peril again, though not because of any outside enemy but rather due to our crumbling infrastructure, outdated energy policies, shortsighted economic policies and a litany of other hazards. We face not the imminent threat of military conquest but instead the chronic threat of slow rot. I think it's worth spending a few bucks to turn that around.
(*Of course, I believe World War II was much more than a government spending program. Anyone who knows me or is familiar with this site knows how I feel about war and how it wastes lives and blasts dreams. If you're not, feel free to poke around the site and see for yourself.)