This article is part of the NBC News Justice for All series.

CAMBRIDGE, Mass. — The rare opportunity to confront Harvard University’s president presented itself last Valentine’s Day, and a group of five students pounced on the chance.

During an open office hour with President Lawrence S. Bacow, the students asked him: How much of Harvard’s almost $40 billion endowment is invested in companies that profit from the mass incarceration of Americans? And would he commit to withdrawing the school’s investment funds from prisons and related companies?

Three of the students had relatives who had spent time in prison. All believed their school should not benefit financially from investments tied to America’s criminal justice system, which incarcerates more than 2 million people, about a third of them black. Private prisons have faced criticism for being less safe for prisoners than government-run facilities and for having a financial interest in people being locked up for long stretches of time.

But instead of securing an ally, members of the Harvard Prison Divestment Campaign said they left disappointed. Bacow, they said, responded that other students were demanding Harvard divest from all sorts of industries these days, including fast food and corn sweeteners. He said he didn’t want the school’s endowment — a fund that supports operations, programs and financial aid for students — to be used as a political statement, an explanation he has also given publicly.

Xitlalli Alvarez, a campaign organizer and Harvard student, called Bacow’s response “dismissive.”

“It was as if he was equating our concern for the suffering of people in prison with corn syrup,” Alvarez, a doctoral student in anthropology, said.

A Harvard spokesman said Bacow "appreciated the opportunity to meet with advocates for prison divestment" and offered to arrange a meeting for them with the Harvard committee that makes endowment decisions.

The students say that has not happened, but they walked out of the meeting energized. Through the spring semester, the group’s 15 core members held protests, collected more than 4,000 signatures of support and interrupted events that Bacow attended with chants of “Disclose! Divest! Or this movement will not rest!” At commencement in May, hundreds of graduates held up orange pro-divestment signs or wore orange over their black caps. Campaign organizers say protests may continue this fall.

Harvard graduates hold up pro-divestment signs while university President Lawrence S. Bacow speaks. Haimy Assefa / NBC News

The prison divestment push at Harvard, which has the largest endowment in academia, is just one in a series of similar movements that have been playing out on college campuses across the country — with varying success.

Over the past four years, at least five university networks or schools — including Columbia University — have agreed to divest endowments or refrain from business with companies that profit from private prisons, said Daniel Carrillo, the executive director of Freedom to Thrive, a Portland, Oregon-based group that began a nationwide prison divestment campaign in 2010.

There are also active student campaigns for divestment at about a dozen universities, Carrillo added, including at Yale University, Princeton University, the University of Chicago and Johns Hopkins University.

“It is an uphill battle,” Carrillo said of the student effort. “Administrations are not typically receptive to student mobilization, student activism or the student voice influencing how things should be done.”

Freedom to Thrive works with students as well as banks, city and state governments, unions and pension programs that have agreed to divest their financial holdings from prison-related companies and private prison firms. The group has tracked close to $5 billion that has been divested, including hundreds of millions of dollars by universities.

The ultimate goal, Carrillo said, is for the United States to move away from building more prisons and for the prison system itself to be abolished in favor of policies that end racial disparities in the criminal justice system and put an emphasis on rehabilitation.

“There’s a narrative in our country that safety for a community is more police, more prisons, a wall,” Carrillo added. “So prison divestment is an important step to get people thinking of a bigger vision for society, but also what concrete, tactical steps to take.”

What's the state of play?

The prison divestment movement has racked up substantive wins.

In 2015, Columbia University announced a policy of divesting from companies involved in the operation of private prisons and to stop making new investments in the industry, becoming the first U.S.-based university to do so. The pledge came after the Ivy League school created its own Center for Justice, tasked with reducing the nation’s reliance on incarceration by advancing alternative approaches to public safety.

The school dumped shares in two firms, including the Corrections Corporation of America, now known as CoreCivic, one of the largest private-prison operators in the country. The company, which is traded on the New York Stock Exchange, manages about 65 facilities across 19 states and earned a net income of more than $159 million in 2018 — down 10 percent from 2017. According to Columbia student activists, the university’s divested shares were worth roughly $8 million.

Bowing to similar pressure from student groups, the University of California school system also fully divested from private prisons in 2015, a move worth about $30 million, as well as Hampshire College in Amherst, Massachusetts, California State University, Los Angeles and Georgetown University, where officials said they would make a conscious effort to avoid investing in private prison corporations.

Additional schools with active prison divestment campaigns include MIT, Swarthmore College, Florida State University, University of Florida, Middlebury College, Portland State University and Grinnell College.

CoreCivic has maintained that it has an important role in supplementing services that state and federal government can’t provide on their own. Spokeswoman Amanda Gilchrist dismissed the negative attention the private prison industry has received, including for its role in housing detained immigrants, as “false information spread by politically motivated special interests.”

“The fact is our sole job is to help the government solve problems in ways it could not do alone — to help manage unprecedented humanitarian crises, dramatically improve the standard of care for vulnerable people, and meet other critical needs efficiently and innovatively,” Gilchrist said.

The GEO Group, the nation’s largest private prison firm, released a statement saying that the divestment efforts “are based on a false narrative and a deliberate mischaracterization of our role as a long-standing government services provider.”

Alex Friedmann, a critic of the private prison industry and associate director of the Human Rights Defense Center, a prisoner rights nonprofit, said he is heartened to see college students rally around the cause of prison divestment.

But their efforts have a long way to go before they can effectively hobble the $5 billion private prison industry, he said. Private prison companies have flourished since the 1980s, when stricter federal drug laws created the need for more prisoner housing. As of 2016, private prisons held 8.5 percent of all state and federal prisoners, according to a report by The Sentencing Project, which advocates for alternatives to incarceration. Dozens of other companies contract with prisons to provide everything from surveillance equipment to prison beds, phone calls and commissary services.

“These very institutionalized social and political issues are fairly entrenched in our criminal justice system,” Friedmann said, “but if enough people want action, we can reach a tipping point for change.”

How much is at stake?

The amount that Harvard’s endowment is tied to the prison industry is unclear.

According to the Harvard Prison Divestment Campaign, Bacow has said the school’s prison-related investments are only $18,000. But based on a review of the 1 percent of the school’s endowment invested in public holdings, the figure is at least $3 million, the campaign found, according to research published in April. The campaign notes that Harvard does not hold direct stock in prison companies, but rather in exchange-traded funds that include companies that build and operate prisons or sell security technology and other products used in policing and detention.

A spokesman for the Harvard Management Company, which oversees the school’s endowment, referred questions to the university, which ultimately makes divestment decisions. The university did not comment beyond confirming Bacow's meeting with the students and saying that he had offered to arrange an additional meeting for them.

The students say that divesting from the prison industry, even indirectly, wouldn’t be out of place for Harvard, where the leadership has previously agreed to pull investments from companies that profit from the tobacco industry, apartheid South Africa and the conflict in the Darfur region of Sudan.

Aside from prisons, some students are also calling for divestment from the fossil fuel industry, a campaign that has seen its own opposition from school leadership. In 2013, Harvard President Drew Gilpin Faust said that the “endowment is a resource, not an instrument to impel social or political change.”

Bacow reiterated that position during a forum on fossil fuel divestment in April, when he also responded to prison divestment. He said Harvard does have its place in contributing to the conversation, but in a different way than divestment.

“I’m proud of what we’ve done as an institution to try through our scholarship to address issues of mass incarceration,” he told students. “I think as an institution, we have much to contribute to this issue. And we should.”

Harvard is home to scholars who have called for changing the criminal justice system, and its law school’s criminal justice policy program has addressed problems surrounding bail, fines and debt.

Members of the prison divestment campaign at Harvard, which is predominantly made up of students of color and started as a class project in the fall of 2017, believe more can be done.

Anneke Dunbar-Gronke wears a mortarboard with a pro-divestment sign. Haimy Assefa / NBC News

This fall, they will host students from more than 30 universities interested in the prison divestment movement and will continue to push a Just Reinvestment Fund — an initiative to get Harvard alumni to stop donating to the school until the campaign’s demands are met. The activists want Harvard to reinvest money from its endowment toward groups that help historically disenfranchised communities of color in the Boston area, focusing on issues such as housing, education and alternatives to incarceration.

For Harvard student Zoë Hopkins, who will be a sophomore in the fall, the past year immersing herself as an organizer was challenging, marked by older Harvard donors who told her she should be arrested for disrupting the school’s president during events.

“Harvard has immense influence,” Hopkins said. “It has a choice: It can either be a leader in making morally right decisions or it can choose to follow and to continue making morally reprehensible decisions.”

“But whatever it does,” she added, “the world is watching.”

Haimy Assefa reported from Cambridge, Massachusetts, and Erik Ortiz reported from New York City.