Bryan (though past his prime in the 20s): Rural racist base and crackpot economic theories that countered elite (and sound) economic understanding. He was an outsider who led the takeover of an ostensibly limited government party.
I initially thought FDR but FDR was much better spoken, though he could be devious. I still think Trump is more like Pierpont Morgan. Gruff, but sharp as a tack and a go-it-alone type. Trump is also opposed to big government.