UPDATED: April 29, 2016, at 1:57 a.m.

Staging a rally and delivering a letter to University President Drew G. Faust’s office, graduate students on Thursday demanded that Harvard remain neutral and not interfere as they push for the right to form a union.

{shortcode-e5681fec35ee77060cd741a497230af9b7c3c206} A group of more than 400 students, faculty, and politicians gathered at the Science Center Plaza Thursday afternoon to stage the rally, which culminated in the delivery of the letter—from the unionization effort Harvard Graduate Students Union-United Auto Workers—to Massachusetts Hall demanding Harvard refrain from any actions that would “delay graduate employees’ right to choose collective bargaining.”

Over 50 Massachusetts state legislators signed the letter, according to Ph.D. student and union organizer Abigail Weil, and other signatories included labor leaders and College students. Faust was not present to accept the letter.

Last spring, graduate students began a movement to unionize, citing the need for the University to recognize students employed by Harvard as workers, and for a representative body to protect their rights.

Top University administrators, including Faust, have repeatedly affirmed their opposition to a union, saying such a move could fundamentally change the relationship between graduate students and Harvard from one of teaching to one based in labor.

In October, Graduate School of Arts and Sciences administrators circulated a letter encouraging faculty to “explain the disadvantages of union membership” to graduate students. However, the document explicitly discouraged hostility toward prospective union members, saying specifically that faculty and administrators should not “threaten” students who support the union with “adverse consequences." In March, Harvard filed an amicus brief to the National Labor Relations Board expressing opposition to graduate student unionization.

Members of the graduate student union effort have called such actions a violation of the neutrality they think Harvard should maintain as they work to form a union. Their letter also demands Harvard refrain from “any effort to influence RAs and TAs in their decision” to vote on whether to unionize and “commence good-faith negotiations for a contract immediately upon confirmation of a majority vote.”

"We will continue to encourage an open, balanced conversation a bout graduate student unionization," Faculy of Arts and Sciences spokesperson Anna Cowenhoven wrote in a statement. "We continue to believe that the relationship between graduate students and a university is fundamentally about education, not employment, and changing that relationship could be damaging and disruptive to graduate education and the graduate student experience."

The event was also a celebration of the majority support, now independently verified by the the American Arbitration Association, that the union effort has among the graduate students Harvard employs.

Graduate students, labor leaders, state and local politicians, and Harvard professors spoke at the event, where organizers displayed the “white boards” of written student support they collected over the course of the past year.

Economics professor Stephen A. Marglin said, “My message is: let the graduate students decide.”

Weil, who led the event, said the union effort has also circulated a neutrality pledge to faculty, urging them to refrain from “public statements, one-on-one meetings, distribution of literature, or any other active campaigning or activities.” She said the petition has “a few dozen” signatures.

“What [professors] need to understand is that it actually has nothing to do with them, so that’s been the thrust of the neutrality pledge,” Weil said.

The NLRB is deliberating on whether or not private institutions must recognize democratically elected graduate student unions. Harvard’s union effort comes in the midst of a flurry of graduate student organizing across the country, including at other private institutions such as Yale and Columbia.

“Harvard needs to understand this: this is a national movement, it’s not going away,” United Auto Workers representative Ellen Wallace said.

—Staff writer Leah S. Yared can be reached at leah.yared@thecrimson.com. Follow her on Twitter @Leah_Yared.