Protectionism and the Great Depression:

Here's a nice video about the Smoot-Hawley tariff, the Great Depression, and protectionism generally. I should note that the idea that protectionism was a substantial cause of the Great Depression is not universally shared. But watch the video anyway, which has good history and good analysis of the ill effects of protectionism. From the folks at Freedom To Trade. (h/t: Tom Palmer)