Thanks, everyone, for some thoughtful and helpful commentary. I’ve updated some sections, added a lot more links, and incorporate a thread from Kevin Pedraja on the shift from isolationism between WWI and WWII to economic and military engagement—especially as it affected the middle class after the Cold War. There’s a few points about China, though probably not enough. And I found more parallels between 1933 and 2016. Finally, an editor at The Huffington Post saw the article and wanted to publish it on the site. Not sure when that will happen, or what kind of hell will be unleashed when it does, but I’ll post another response here about it when I can.