New York City Mayor Zohran Mamdani and members of the City Council are on a collision course over a housing bill whose supporters contend it will help keep more apartments affordable and out of the grip of speculators.

The mayor is publicly backing legislation that would give nonprofits and some private developers first dibs on distressed apartment buildings, after former Mayor Eric Adams vetoed the Council-backed legislation on his final day in office.

Mamdani’s support for the Community Opportunity to Purchase Act — which he campaigned for during his mayoral run — sets up a potential conflict with Council Speaker Julie Menin. She has not yet said where she stands on the controversial measure, as support wavers over a possible vote this week to override Adams’ veto.

The bill, known as COPA, would allow organizations and housing developers to bid on buildings with serious housing code violations or expiring affordability agreements, for up to three-and-a-half months before the properties hit the open market. The legislation’s backers argue the advance notice is necessary to boost the odds of maintaining such units as affordable.

The Council passed the measure late last year. Adams then vetoed it in response to opposition from the real estate industry and landlord groups, who contend it would increase red tape and ultimately reduce the city’s housing supply. Proponents said it would affect just 1% of housing transactions, but that would still mean many thousands of apartments would be affected.

Mamdani is now urging the Council to override the veto, even as some members back off their initial support for the legislation. The deadline for a veto override vote is Thursday, and observers have described intense backroom negotiations over the bill’s fate.

“Let’s be clear: Mayor Mamdani has long supported the Community Opportunity to Purchase Act, and still does,” City Hall spokesperson Dora Pekec told Gothamist. “After productive discussions with the City Council and the Law Department, we hope the Council will pass it on Thursday.”

Will Spisak, a senior policy strategist at New Economy Project, a nonprofit that supports the legislation, said COPA was needed to keep tenants from being displaced, particularly in gentrifying communities of color.

He estimated that out of 51,000 buildings sold each year across the five boroughs, just over 500 would be eligible under the bill, but these buildings include “a significant number of units of affordable housing that are in danger of being lost.”

“We need to build deeply and truly affordable housing across New York City, but we also need a comprehensive preservation strategy to preserve the affordable housing we already have," Spisak said.

He said the legislation last week appeared to have secured a 34-vote supermajority, enough to override Adams’ veto. But since then, he said, some councilmembers have withdrawn their support in the face of lobbying by real estate interests.

By Spisak’s count, just 31 councilmembers now back the measure, similar to the vote total in December, when the bill was adopted in a 31-10 vote. Menin, who was a councilmember at the time, abstained. She was subsequently elected speaker.

Asked where Menin stood on the override, her spokesperson Jack Lobel issued a noncommittal statement on Tuesday, leaving the possibility of an override vote in doubt.

“The City Council is ready to override bills that have a clear supermajority of support,” Lobel said.

Supporters on the Council continue to press their case. Councilmember Sandra Nurse, the bill’s sponsor, said in a statement late Tuesday that the “modest, targeted bill” would preserve thousands of affordable homes.

“New Yorkers living paycheck to paycheck are leaving our city,” Nurse said. “COPA is one of the tools we need to preserve affordable housing, protect tenants in at-risk buildings, and stop faceless investment firms and LLCs [limited liability companies] from buying up our neighborhoods.”

Deliberations over the bill have gotten heated, with members of the nonprofit Small Property Owners of New York, or SPONY, angrily shouting at members of the Council’s committee on housing and buildings after the panel unanimously voted in support of the bill on Dec. 18, sending it to the full Council.

Ann Korchak, board president of SPONY, said in a statement on Tuesday that “COPA will make New York City an affordable housing wasteland and trigger the extinction of small owners.”

James Whelan, president of the Real Estate Board of New York industry group, said the legislation, if enacted, would mean less housing being built across the five boroughs.

“The city will pay more per unit, deliver fewer homes overall and continue to fall short in producing at a scale New Yorkers need,” he said in a statement. “Our housing crisis will worsen and the city will become even less affordable.”

Some housing experts have raised concerns about the scope of the legislation and whether nonprofits are better equipped to take on more distressed properties.

“There are nonprofit affordable housing owners and operators, great organizations around the city, that today are struggling with the buildings that they have,” said Howard Slatkin, executive director of the nonprofit Citizens Housing and Planning Council. “There are some real, serious financial challenges to subsidize affordable housing.”

Brad Greenburg, deputy director of NYU’s Furman Center, said the full reach of the bill was unclear but it would have financial costs.

“Any time you add more legal process to a transaction, it does introduce costs,” Greenburg said. “The question for policymakers is whether the costs are going to outweigh the benefits we end up realizing.”