When members of the Progressive Student Labor Movement (PSLM) took on the campaign for a living wage for Harvard’s workers nearly four years ago, they found themselves fighting a powerful University.

With Harvard’s lowest-paid workers faced with the constant threat of outsourcing and the union representing them out of touch with its membership, PSLM was the only game in town.

Students were in the driver’s seat—staging their own protests, making their own claims, deciding to push for the City of Cambridge’s living wage formula as the one the University should adopt.

But as the Living Wage Campaign picked up steam, workers and a newly revamped Service Employees International Union (SEIU) Local 254 were pulled along by the students’ energy.

Spurred by PSLM, workers and unions joined with the students to form a far more formidable opponent than Harvard’s administration had faced in years.

The strength of the partnership became clear last spring, as PSLM members forced the University to agree to renegotiate workers’ contracts with a three-week long occupation of Mass. Hall.

Students benefited from the experience, size and credibility of unions. AFL-CIO President John Sweeney’s speech outside the sit-in to thousands of students, media and workers mobilized from throughout the area was national news.

And Sweeney’s negotiators helped broker a deal with administrators who had previously refused to consider any compromises to end the sit-in.

While the unions benefited from the energy brought by PSLM, the students bolstered their cause with the support of unions skilled in bargaining and well-connected with the actual workers.

Labor experts say this sort of cooperation marks an important new trend.

“The labor movement has been ruled by a group of old white men for a long time, and those old men are getting old and they’re leaving,” says Kate Bronfenbrenner, director of labor education research at Cornell University. “Young people coming in are waking them up and challenging them.”

Yet some of PSLM’s greatest victories on behalf of workers have demonstrated the limits of student power in the world of labor relations.

As PSLM members pushed the issue of higher wages onto the bargaining table, it entered a realm in which they as students could merely be supporters, not leaders.

With SEIU in charge of contract negotiations, PSLM—with its years of contact with workers—worries that the hierarchical union, however revitalized, may still not be the best advocate for workers’ concerns.

The irony is that without PSLM’s activism pushing the living wage and the union to the forefront, this spring’s wage hikes might never have happened. But with the student group’s success has come uncertainty about the role students can play in organizing workers once they have helped the union regain power and credibility.