The National Labor Relations Board has gone back-and-forth on whether graduate students at private universities can form unions three times in the past 19 years.

Observers expect that the National Labor Relations Board will reverse an Obama-era determination that graduate students are employees entitled to form unions.

Administration officials contend that research and teaching assistants are students, not workers, and want to take the matter to federal court.

Student workers seek voluntary recognition of their unions by university administrators out of concern that political appointees may deny their unions legal status.

The university’s administration tried unsuccessfully to stop the vote.