Student workers at private colleges and universities across the country can now join labor unions.

In a 3-1 decision announced Tuesday, the majority Democratic National Labor Relations Board (NLRB) decided that Columbia University graduate students who also work as teaching assistants at the school are considered employees under federal labor law and have the right to unionize.

Many graduate students at public universities have already formed collective bargaining units, as they are governed by state labor laws, however students at private universities have not been able to do so since 2004.

According to the board, the National Labor Relations Act “contains no clear language prohibiting student assistants from its coverage,” and the majority of the board “found no compelling reason to exclude student assistants from the protections of the Act.”

The Wall Street Journal reported that this decision “would deliver tens of thousands of young, educated potential members to the ailing labor movement—and a giant headache to some of the most prestigious universities in the country.”

Universities will now have to work around union rules, which could dictate which students are allowed to teach certain classes. They'll also be forced to provide increased compensation for teaching assistants.

Other Ivy League universities Harvard and Stanford filed a joint legal brief opposing Columbia’s petition to unionize. They argued that universities don't function like a workplace. Students aren't just working for wages, they are working as part of their curriculum, while also receiving financial support from their school in the form of tuition grants, health-care coverage, and stipends for living expenses.

The Service Employment International Union (SEIU) was prepared for the decision and is already working with graduate students at Duke, Northwestern, St. Louis University, American University, and other colleges to form unions.

"Colleges and universities that used to provide a pathway to the American Dream are now becoming a road to poverty for students who find themselves saddled with debt and graduate workers and faculty who are unable to support their families on low pay," SEIU President Mary Kay Henry said in a statement. "Restoring the rights of graduate workers is a critical step in ensuring that those on the front-lines of teaching and researching at colleges and universities have a voice in improving higher education for all of us."