alt Hacker NewsTwo others:
Bernie Sanders (prevented from winning the primary via unelected superdelegates)
Ross Perot (suddenly withdrew under murky circumstances and later claimed his family was threatened)
Both wanted significant change, although they were reformists rather than revolutionaries.
Am I missing something here? Perot was on the ballot in 1992, and he won a bunch of votes. IIRC he was the most successful independent candidate in modern times, by vote count.
Sanders ran an insurgent campaign while denigrating the party, and didn't win more votes. I seriously don't understand the argument that the person with fewer votes should win the nomination, although I am receptive to hearing a coherent articulation thereof. (Superdelegates did not enter the picture until tens of millions of votes were cast, with Sanders trailing by millions of votes.)