Six of Yale’s academic departments voted to join graduate student union Local 33 on Thursday, paving the way for graduate students to bargain collectively for the first time in University history.

Math, Sociology, History, History of Art, English and Geology and Geophysics all voted to join Local 33 in labor elections. The Physics Department voted against joining the union. In the final two departments — Political Science and East Asian Languages and Literatures — the number of challenged ballots exceeded the voting margin, meaning that those elections remain undecided.

After the results in Sociology, History, History of Art and English were announced at Dwight Hall, around 60 supporters of Local 33 who had gathered to watch the vote count erupted into cheers, embracing each other as they celebrated a victory decades in the making.

“It’s really exciting in this moment, nationally and for grad workers and other kinds of academic workers, for there to be an important victory like this one,” said Local 33 Chair Aaron Greenberg GRD ’18. “It’s meant so much over the past few years to be part of a larger movement of grad workers who are doing the hard thing and organizing.”

The atmosphere in Founders Hall on Prospect Street — where the results in Math, Geology and Geophysics, and Physics were announced — was more mixed. Fighting back tears, Local 33 Co-Chair Robin Canavan GRD ’19 said she was thrilled with the result in her home department, Geology and Geophysics, but was disappointed that the union lost in the Physics Department.

“It has really been a long struggle to get to this day and to vote,” Canavan said. “I always thought we would, I just never really knew how or what it would look like.”

Only the roughly 300 students teaching in the nine departments this semester were eligible to vote in the Local 33 elections. The union won the History Department by 39 votes to 7; the English Department 22 to 4; the Sociology Department 12 to 3; the History of Art Department 17 to 2; the Math Department 8 to 3; and the Geology and Geophysics Department 9 to 7. The Physics Department voted 30 to 26 against joining Local 33.

But students in Political Science and East Asian Languages and Literatures will have to wait to learn whether their departments can join Local 33. A provisional vote count in Political Science shows the union leading 19 to 14. But another 25 votes — cast by graduate and professional students teaching in political science this semester — are under challenge, and must be reviewed by the National Labor Relations Board before they are counted. In East Asian Languages and Literatures, the provisional vote count shows Local 33 leading 5 to 1, with 16 challenged ballots yet to be counted.

In a statement, Graduate School Dean Lynn Cooley said the election results “demonstrate the extent of graduate student division on the question of unionization,” and promised that the University will respond in greater detail in the coming days.

“The union lost one of its own hand-picked departments, and failed to clearly win two others, with opposition spread across the physical sciences, social sciences and humanities,” Cooley said. “The slim margins of victory and very low vote counts in many departments only underscore the concerns many have voiced that a small number of students could be in the position to decide such an important question for everyone.”

Thursday’s elections marked a turning point after six months of legal disputes between the University and Local 33. Indeed, Yale’s latest effort to block the union elections was not resolved until Wednesday, when the NLRB dismissed a request for review from the University that challenged the legal foundation of Local 33’s department-by-department strategy.

On Thursday at the stroke of 9 a.m., a long line of union supporters wearing orange Local 33 pins marched across Old Campus to Dwight Hall, where students in the humanities and social science departments were scheduled to vote.

After casting his ballot in favor of Local 33, political science student John Dearborn GRD ’19 said he voted to unionize because of concerns about the health care coverage offered by Yale, especially the lack of dental support. A few hours later, Local 33 supporter Ittai Orr GRD ’20 — an American Studies student teaching in the English Department — let out an enthusiastic whoop as he left Dwight Hall at the end of a stressful morning in which he also took a high-pressure oral exam.

“I am so happy,” he shouted, embracing a crowd of his friends.

Yale has fought graduate student unionization since the formation of the Graduate Employees and Students Organization — the precursor to Local 33 — in the early 1990s. In the fall, the University hired the traditionally anti-union law firm Proskauer Rose LLP to challenge the union’s departmental strategy in front of the NLRB.

But after voting on Thursday, Orr told the News that Yale’s opposition — including a recent communitywide email from Cooley that outlined objections against Local 33 — actually encouraged the union movement in the weeks leading up to the election.

“It was energizing,” Orr said. “Cooley’s email was a welcome sign of desperation.”

Orr was joined at Dwight Hall by his husband Jason Fitzgerald, a graduate student at Columbia who voted to unionize in the elections held there last December. Since the NLRB decision last August, both Harvard and Columbia have held union elections, although ongoing legal disputes have left the outcomes undecided.

And despite Local 33’s victories on Thursday, a similarly prolonged legal battle could await graduate students at Yale, according to Dan Bowling, a labor expert at Duke School of Law.

According to Bowling, the losing side in a labor election often files objections with the NLRB in a last-ditch attempt to reverse the outcome. And given that Yale has opposed Local 33 at every stage in the process so far, it would be unsurprising if the University challenged the union vote, he said.

“It looks like they’re playing hardball, and that’s perfectly appropriate and legal, if they choose to do that,” Bowling said.

Meanwhile, the NLRB will hold hearings in the coming weeks to decide the eligibility of graduate and professional students who participated in the elections in Political Science and East Asian Languages and Literatures.

After the NLRB resolves those eligibility questions, Local 33 will likely seek to begin the bargaining process with Yale as soon as possible, Bowling said.

“They’re going to try as quickly as possible get Yale to come to the table and agree to some contract on some issues,” Bowling said. “Most union advisors would say get some contract, get the bargaining relationship established. You don’t get your entire wish list on the first contract.”

In theory, the first Yale-Local 33 contract could cover all the departments that voted to unionize, or it could take the form of a master agreement with separate clauses for individual departments, Bowling added.

But the contract was not a major topic of discussion Thursday night, as student organizers posed for pictures on Old Campus and made plans for late-night drinks.

“We’re really focused on just how exciting it is that our colleagues across the University decided to vote yes to take us into our next step, which is really coming together, figuring out our priorities and sitting down to negotiate with University administrators about the issues that matter to us,” Greenberg said.

Over the course of the year, Local 33 has faced significant opposition from students in the Graduate School, who argue that the departmental election strategy is undemocratic and that the union’s recruitment strategies are overly aggressive. In October, the Graduate Student Assembly voted to oppose Local 33, breaking years of silence on labor issues. And in the wake of that vote, the anti-Local 33 group GASO unveiled a new website detailing objections to the union’s election strategy.

Alexandru Georgescu GRD ’17, a student in the Physics Department who helps run GASO, said opposition from older students in the department may have swung the physics election away from Local 33.

“The reason I think upper years are more against them is because we’ve been at Yale longer, heard about what happens in various departments,” Georgescu said. “The more you ask [Local 33], and get only very vague, confusing answers, the less likely you are to vote for them.”

The only private university with a graduate student union is New York University.

This article was updated to reflect the version that ran in print on Feb. 24.