The battle over whether graduate students at universities can unionize entered a new phase on Friday, when Columbia University filed a challenge with the National Labor Relations Board over the recent vote by its graduate assistants to unionize.
Columbia said that tactics like voter coercion may have tipped the balance in favor of the union and that the N.L.R.B. should invalidate the vote.
At a rally at the Morningside Heights campus in Manhattan on Monday, students said the university was trying to drag out the fight, possibly until President-elect Donald J. Trump could appoint new members to the labor board, tipping the balance in a direction more likely to favor Columbia.
The issue has gone back and forth depending on the makeup of the board, which said in August that graduate students at private institutions had a federal right to unionize. That decision overturned a ruling from 2004 that said graduate students at Brown University could not do the same.
The rules for public universities are different. There, states can decide if graduate students can unionize.
In its objections, Columbia said that during the election, “known union agents” stood within 100 feet of a polling place — an area voters had to pass through in order to vote — and had conversations with eligible voters.
Columbia also faulted the regional body of the N.L.R.B., saying a last-minute decision not to require voters to present identification might have allowed ineligible voters to cast ballots. Columbia said a board representative improperly removed an election observer.
A couple of dozen graduate students gathered on the steps of the Low Memorial Library at Columbia on Monday to protest. They called the university’s challenge a delaying tactic, and they called it that in a Christmas-themed song, no less.
To the tune of the Christmas song “Sleigh Ride” — “come on, it’s lovely weather for a sleigh ride together with you” — the protesters sang:
“Hear that endowment ring-a-ling-ting-ting-ting-a-ling, too.
Because the admin’s trying to break our graduate union!”
“Wait for Trump, wait for Trump, wait for Trump, they say,
he’ll take it away! We’ll scheme to subvert the landslide ‘yea.’”
In an emailed statement, the university took a more bureaucratic approach.
“Our objections were filed with the N.L.R.B. as part of its established procedure for determining whether the conduct of the election was appropriate,” said Robert Hornsby, a Columbia spokesman. “We share the N.L.R.B.’s goal of ensuring a fair electoral process and protecting the rights of all students.”