Smith, out of distaste for Republican corruption, distaste for the anti-Catholicism and dismay at the death of Progressive republicanism.
What Republican corruption? You talking about the deceased halfwit, Harding?
Hoover was a "progressive," by all means.
Mostly the Tea Pot Dome, or whatever it was called, yes. But considering how the GOP won the 1924 election despite it I would have wanted them punished, I think. And I don't believe Hoover was a progressive (you might view him as too leftist, yes, but the Progressive Republicans were pretty much over by 1928). I would probably have voted for Bob LaFolette in 1924 and been a Roosevelt supporter back in his days, so I would have been displeased with the rooting out of Progressive Republicans.