On Monday, student organizers announced that Columbia University’s board of trustees had voted to divest from the private prison industry, a victory for the nearly two-year campaign led by the student group Columbia Prison Divest.

The vote mandates that the university sell its 220,000 shares in G4s, a British prison and security services company that operates prisons across the world and provides equipment for Israeli-run checkpoints in occupied Palestine. Furthermore, Columbia has pledged never to invest its $8 billion–plus endowment in other private prison corporations like Corrections Corporation of America in which, according to student estimates, the school had $8 million worth of shares as of June 2013.

These investments, it should be said, are a drop in the bucket for an industry that brings in roughly $3 billion in revenue annually by operating prisons, jails, and holding facilities for undocumented immigrants. Students argue their campaign was not intended to make a huge dent in the profit margins of these corporations, but instead to increase awareness of the industry, and mass incarceration more broadly.

“These are billion-dollar corporations,” Columbia Prison Divest organizer Gabriela Pelsinger told me. “If we hope to see an end to this, we have to look to and expose the economic engine driving this exploitation and incarceration, which is in large part due to the lobbying and the political presence of the private prison industry.”

The impetus for the campaign stems from a visit then-sophomore Asha Rosa and a friend took to the university office tasked with “socially responsible investing” in December 2013. There they inquired about where Columbia was putting its money, and subsequently discovered that the university had at least $10 million directly invested in private prison companies. “As soon as we saw the list, it was never a question of if we’re going to do something,” she says.

On Febuary 3, 2014, a group of about twenty students walked into the office of Columbia President Lee Bollinger and read a letter demanding the school divest from the industry.

But from the very beginning, Columbia Prison Divest knew it would have to do on-the-ground organizing to get their message out directly and unfiltered. In the Columbia Spectator’s first article on the campaign, for example, the newspaper excised organizers’ references to Palestine and claimed that the main point of the effort was to make the university’s financial information more transparent.

So instead of relying on media attention to get their message across, Columbia Prison Divest built power by building deep roots within the school community, actively reaching out to students and faculty on a weekly and sometimes daily basis. “Organizing media is important but it can never replace organizing people,” Rosa says.

“We had a sheet up on the wall in my room with all our goals. There are three of them that we circled and highlighted: one: divestment, two: educate people about systems of prisons and policing, three: contribute to the broader prison abolitionist movement,” Rosa explains. “We told ourselves that we didn’t win if we didn’t fundamentally change people’s minds about everything from mass incarceration to Palestine. We didn’t win if we didn’t connect to larger movements in the city. Columbia divesting 10 million isn’t going to make CCA and G4S fall, so how you do it is just as important.”

The modern iteration of the American private prison industry emerged in the mid-1980s, a response to the overcrowding and rising costs of state prisons caused by the racist “war on drugs” and “tough on crime” legislation. Through persistent lobbying and legislative influence, private prison corporations have grown to incarcerate 19 percent of the federal prison population and 7 percent of the state prison population.

It was this sort of information that organizers disseminated through regular tabling, pushing interested students to develop a deeper understanding about the ways in which the rise of the private prison industry was inextricably linked to mass incarceration and capitalism.

“The campaign was launched by students in an older group called Students Against Mass Incarceration, which grounded us in an antiracist, anti-carceral, and anti-capitalist politics,” says Dunni Oduyemi, an organizer with Columbia Prison Divest. “So we based our political education for the community and our messaging off of that. We wanted to get the liberal Columbia students, but not allow our messaging to become about some vaguely liberal neat solution.”

It wasn’t enough, in other words, to just convince people that private prisons were the problem. “When we first started and were talking to folks with just about no political consciousness we would say, ‘This is why private prisons are bad,’” Rosa says. “But eventually we decided to shift to what we really meant: ‘All prisons are violent degrading institutions, let’s think about how private prisons fit into this.’ We asked ourselves, ‘How can we most honestly organize?’ We didn’t want to win through a fiscal argument like the Koch brothers.”

The group’s conscious work to make the campaign an expressly political and broad-based movement, more racially diverse than any in recent memory at the school, gave the campaign a feeling of inexorable momentum.

Whereas campus support and membership in Columbia’s anti-sexual violence group, No Red Tape, dwindled over the year — the result, many activists claim, of a leadership mostly interested in garnering outside attention through high-profile but poorly attended media stunts — Columbia Prison Divest’s democratic approach kept its ranks continually swelling, despite receiving considerably less attention from New York’s media elite.

Galvanized by Black Lives Matter, the group took increasingly militant actions, marching through campus, confronting Bollinger on his way to class, packing town hall to pressure administrators, and capping off the year with a sit-in outside the president’s office. “We used multiple strategies, some of them were through the university’s bureaucratic process, knowing that structure wasn’t created for us to win,” Rosa explains. “We said we’re going to do your process President Bollinger, and we’re also going to show up to every university event you do.”

By the final sit-in, Oduyemi says, almost every campus social justice group had come out in support of the cause, from Students Against Mass Incarceration and the Black Students’ Organization to Students for Justice in Palestine and Student Worker Solidarity. And beyond Columbia’s traditional left, community members, organizing against gentrification and policing in West Harlem, came “up the hill” to show solidarity.

According to Taylonn Murphy, a West Harlem community activist, who attended many of Columbia Prison Divest’s actions, “We felt it was very important for us to come out because this whole investment in the private prison industry affects our community. It puts pressure on the system to imprison our youth. We feel that an institution such as Columbia should understand this is a human rights issue and travesty.”

Though Columbia Prison Divest’s victory is the first of its kind on a college campus, it reflects the fact that America’s system of mass incarceration, approaching levels of imprisonment unseen since the height of Stalin’s gulags, is increasingly entering the public consciousness.

And the momentum for prison divestment now seems to be spreading beyond Columbia’s campus, evoking the campus struggles of the 1980s that demanded divestment from apartheid South Africa. Since 2013, five University of California student senates have passed resolutions calling for divestiture from the private prison industry, and students at the City University of New York, Wesleyan University, and New York University are organizing to follow Columbia’s lead as well.

In order to win, they too will have to build collective power — the kind that can’t come from snappy press releases or headline-grabbing strategies alone. It will still take the stuff of good, old-fashioned organizing: the 6 AM wake up calls, the one-on-ones, the testy late night strategy sessions, the teach-in preparations, the lunchtime tablings, the cold winter flyerings — the crucial nuts and bolts that no one takes pictures of and outsiders take for granted.

But if the prison divestment movement spreads to more college campuses, if it can connect with Black Lives Matter, the prison abolition movement, and the ongoing immigrant rights struggles — from which these divestment tactics were originally born — it may be able to challenge the $3 billion private prison industry on more than a symbolic basis.