"The progressive left" and "the labor left" increasingly don't get along with one another.
I don't think that a bunch of corrupt bosses who are chummy with Cuomo are representative of the labor left.
So union bosses are corrupt? Is that an official statement? Do we apply that to all union bosses or just the ones that support Cuomo? If we're only applying that to the ones that support Cuomo, that's a pretty poor argument unless you have evidence on these particular union bosses that demonstrates they are corrupt that we can pass on to the New York SBI.
Democrats' hold on labor has been weakening for some time. Obama did not give a sh**t about them and national labor bosses in 2012 said as much while still supporting the Democratic ticket. I also wonder how many union labor voters Trump won in the 2016 election - rank-and-file, not leadership. Tariffs is also a pro-union issue for a lot I'm thinking (I don't back tariffs, but I think a good number of rank-and-file union members do.) Public service labor's opinion of my local decade-long Democratic Party Mayor is he sold them out and threw them to the wolves (city council) to lose collective bargaining. They responded by not volunteering at Democratic Party campaign activities.
Get down into policies, progressives and labor voters are just diametrically opposed to one another on a number of issues. Otherwise, why is the WFP splitting? Progressives are Waxman and labor are Dingell to recall an infamous committee chair switch.
This is a deeply flawed argument.
Did you see the extremely high amount of union organizing for Connor Lamb in the PA-18 special election? You had both rank-and-file, and the union leadership coming out in heavy support for progressive democratic policies ($15 dollar minimum wage).
The argument about the inevitable conflict between the 'union left', and 'progressive left' is one that's been around the 1960s, and I'm always skeptical of the extend to which people take it. If you polled the vast majority of 'progressive' Democrats, and 'union' Democrats they'd agree on free trade being harmful, on a $15 minimum wage, and probably even on social issues like Gay Marriage, and Abortion.
This isn't 1968.
The split in New York is not at all about policy. Andrew Cuomo is as much a social liberal as anyone, and is certainly not high on my list of 'union friendly' politicians. But he's a sitting Governor, with a national profile, a long contact book, and a large amount of money. Trade Union bosses aren't going to split from him to join Cynthia Nixon.
Even if someone with experience in NY politics, like De Blasio or Scheinderman was running against Cuomo, I wouldn't expect the unions to jump ship. These types of petty battles between surrogate groups happen in every Democratic Primary.