http://www.sciencemag.org/news/2019/09/grad-student-unions-dealt-blow-proposed-new-rule-says-students-aren-t-employees

Graduate students at Columbia University went on strike in 2018 after the university refused to recognize their union.

Graduate students are not “employees” with a right to unionize, according to a rule proposed today by the National Labor Relations Board (NLRB), an agency that’s tasked with enforcing U.S. labor laws. If implemented, the rule would undercut a recent wave of grad student unionization efforts at private U.S. universities. The NLRB will be accepting public comment on the announcement for 60 days.