A FOUR-MONTH-OLD opinion piece published in CommonWealth is igniting fresh controversy.

On Friday, a group of minority, union, and liberal organizing groups – including the Boston chapter of the NAACP, Neighbor to Neighbor, City Life/Vida Urbana, Community Labor United, and others — wrote an open letter calling on Pioneer Institute senior fellow Charles Chieppo to resign.

The issue is an op-ed Chieppo wrote, published in CommonWealth on June 26, which stated that outrage over the killing of George Floyd, a black man killed by a white police officer in Minneapolis, called attention to police unions’ resistance to reforms. Chieppo went on to argue that the police unions are similar to other public sector unions that have resisted reforms. He highlighted in particular the sway held by Massachusetts’ public transit and education unions in preventing the privatization of MBTA functions or stunting the growth of charter schools.

“In states like Massachusetts, police are hardly alone when it comes to using enormous political influence to block common-sense reforms,” Chieppo wrote. “The brutal killing of George Floyd should remind voters of the threat concentrated power poses to a healthy democracy.”

The organizing groups wrote a seven-page letter attacking Chieppo for exploiting Floyd’s killing. No one from the organizing groups signed the letter.

“Chieppo exploited the name and murder of George Floyd in a manner that warrants Chieppo’s resignation, along with an apology from the Institute to all Black Massachusetts residents and from any leader within the Institute who authorized Chieppo’s erroneous evocation of Floyd’s name to grind a political axe,” the groups wrote.

Pioneer Institute Senior Fellow Charles Chieppo.

They continued, “What makes the white, arch-conservative Chieppo feel entitled to evoke the name of Floyd in his diatribe against educators and transit workers is a question that Pioneer must grapple with.”

The groups argue that “the exploitation of Black death to push an unrelated political agenda” should have rendered the op-ed “unpublishable.”

The letter also includes an extensive denunciation of the Pioneer Institute, which the letter says has for years fought “tooth and nail against public policies and programs that advance the interests of Black people, Black workers, and Black communities.” The liberal groups criticize Pioneer for anti-union policies, noting that unions represent large numbers of black workers, and for remaining silent on the Black Lives Matter movement. They also question the Pioneer Institute’s funding sources and ties to various conservative national organizations, such as the American Legislative Exchange Council.

They are demanding that Pioneer Institute fully disclose its funders, and they are calling on all media outlets to refuse to publish materials submitted by the Pioneer Institute.

The Pioneer Institute is a free-market think tank that leans conservative. One of its former executive directors is now-Gov. Charlie Baker, a Republican. Chieppo, who served as policy director in the Executive Office for Administration and Finance under Republican Gov. Mitt Romney, was a member of an MBTA funding-related commission in 2000 and now runs his own communications consulting firm.

Jim Stergios, executive director of the Pioneer Institute, said in a statement that powerful unions can be “very resistant to change” and prioritize protecting their own members, even when those members harm or kill others. “Pioneer is hardly the first to point out this obvious fact,” Stergios said. Stergios said Pioneer has done a significant amount of work on civil rights issues. “We understand that it would delight cancel-culture warriors to drag Pioneer through their Robespierreian ‘courts,’ but they don’t have a leg to stand on,” Stergios said.