There were probably very, very few people who switched like that in 1932.
Smith himself? (Had he lived to see the 1944 election?).
This is a good guess, but Smith himself supported Roosevelt in 1932, as did many conservative Democrats who later came to oppose FDR's presidency.
Interesting. It sounds like Smith himself would have voted exactly this way then if FDR had given more detail on his New Deal plans in 1932, and if he had lived to see the 1944 election. Same for John W. Davis (who voted FDR, then for the GOP in 1936, 1940, and 1944)
