With the current rift between the Bernie and Warren camps, I’m reminded of the split between Robert La Follette and Theodore Roosevelt in 1912. To quote
Wikipedia: Roosevelt entered the campaign late as Taft was already being challenged by Progressive leader senator Robert La Follette of Wisconsin. Most of La Follette's supporters switched to Roosevelt, leaving the Wisconsin senator embittered.
Even in 1924, there was some grudge between the two camps, with Hiram Johnson (TR’s 1912 running mate) still disliking La Follette despite agreeing on policies.
Warren or Bernie would clearly not support Trump over the other (or any other Democrat), but there is clearly bad blood between the two of them now.
Any thoughts on the comparison and what the future of progressivism in the US may bring?