Graduate student union organizers on private campuses hailed a 2016 decision from the National Labor Relations Board saying that teaching and research assistants at Columbia University were in fact employees entitled to collective bargaining rights. Graduate unions at other private institutions flooded the board with petitions for elections and, in a number of cases, gained majority approval. That was then. In a sign of how much things have changed, three unions withdrew petitions pending review by the board within the last week.