The International Association of Machinists and Aerospace Workers trumpeted an agreement reached earlier this month to represent New York Uber drivers, saying it "gives organized labor an opportunity to shape the new economy in a way that supports and values workers and their families."

But not everyone in the U.S. labor movement is cheering.

The deal falls short of actual union representation, and it has revealed sharp divisions among labor advocates about how to address a central reality of the so-called gig economy: The classification of workers as independent contractors rather than employees. Read More