We've talked about the Bonus Army being a flashpoint for a revolution before, but there are serious plausibility problems with them becoming a communist revolutionary front during Hoover and seemingly little interest in seeing them as a fascist or business-oligarchy backed force during FDR. So I was thinking about a different tact.
Let's say the Bonus Army A. is compelled and able to become a large, powerful, and permanent organization and B. is successful in a coup to take control of the government rather than causing a long and drawn out Spanish style civil war. Implausible, but we're going with the low odds angle here to make a point, to examine a social experiment.
My premise to you to think on is what if the Army did not move in a socialist or fascist direction per se, but C. put the nation on a war economy as a method of dealing with the Depression and D. came under the unlikely influence of the government's technocracy advocating thinktank(s). I'm also thinking of a coup that leads to a swift change but doesn't abolish the democratic government, in a manner similar to the origin of the Fifth Republic in France.
So in a nutshell my premise is a utilitarian alternate United States in the 1930's and 40's.