It's mindblowing to think that the political parties have flip flopped in that sense, this same thing happened in Canada and the UK too. I think a similar flip flop happened with which party represented the "common man" or the "working man". The left wing had this locked up until some time in the 80's, then the right figured out how to appeal to this group.

Here's one story of how "mind-blowing" it is. Most history professors teach that the Republicans were largely to blame for the Great Depression, and how it's an example of the free-market gone awry.

That's "partly" true - the Republicans certainly contributed greatly to it, but their actual actions are those that people would more commonly attribute (today) to "liberals". The Republican leaders, especially Herbert Hoover, were heavily pushing government manipulation of the money supply and forcing "easy money, easy credit" policies that ultimately contributed to the Depression. A few Democrats at the time were opposed to these policies and voiced strong opinions. So yes, the Republicans were to blame, but not for the reasons often provided. History professors are funny that way...