The National Labor Relations Board (NLRB) is expected to review whether graduate students should be considered employees of a university. If the NLRB finds that they should not be considered employees, these graduate students could lose their right to unionize. The NLRB had previously considered them to not be employees until a case in 2000 when the board sided with the "students". The board then sided with the universities in a case just four years later. Thus the board has commonly flip-flopped over its view on this topic. At this time the NLRB has not set an exact date to address this issue.
See "Are Grad Students Employees? Labor Board To Again Weigh In", Yuki Noguchi, NPR, April 8, 2016