Let's say, for whatever reason, that Al Smith is elected in 1932. Let's say FDR isn't there to oppose him at the Convention, maybe Smith didn't run in 28, etc. Given that it is 1932, I think Smith would win despite anti-Catholic sentiment, solely on the grounds that he isn't Hoover.
So, how does he govern? In what ways is he like that other progressive former Governor of New York, and in what ways is he different? What happens next?