When you look at the sheer magnitude of the Harding and Coolidge landslides outside the south in both urban and rural areas; including in many places that had been and would later be Democratic strongholds it seems like the sort of landslide that really never could have happened at any time before or since. Even in 1972 and 84 the Democrats had a large enough swath of loyal voters they had the upper hand with on cultural and economic issues that kept Nixon and Reagan from having a chance of hitting the same sort of popular vote ceiling that Harding and Coolidge did.
It honestly seems like without Al Smith in 28 followed by the depression the Democrats would have been reduced to the status of the Liberal Party in the UK with LaFollette's Progressive Party evolving into an American version of Labour. Thoughts?
I mean it depends on what exactly is meant by polarisation: ideological, racial, sectional, partisan? But my answer would be that "outside the South" is operative here. Even in 1920 Cox won more than half a dozen Southern states by 30 points or more, while losing by 26 points nationally. That sort of sectionalism just didn't exist in the later 20th century.
More than Al Smith and the Depression it was the Solid South that saved the Democratic Party from going the way of the British Liberal Party (in the 1890s as well as the 1920s).
