THE NEW BEDFORD SCHOOL COMMITTEE voted 5-2 on Thursday night in favor of a precedent-setting expansion deal with a local charter school operator, but even the five supporters insisted they didn’t like the arrangement and were voting for it only because state officials were figuratively holding a gun to their head.

The school committee vote approved a memo of understanding between the city, the Alma del Mar Charter School, and state education officials that will allow the charter to open a K-8 school with 450 students.

The arrangement is precedent-setting because Alma del Mar will only enroll students from the neighborhood surrounding its school rather than filling its seats through a citywide lottery, as called for in the state’s existing charter school law. New Bedford will guarantee Alma del Mar 450 students; the school won’t have to scramble to sign them up. The deal between New Bedford and Alma del Mar is the first time a charter school and a school district have merged their enrollment systems, which many public school supporters in New Bedford view as a betrayal.

“We have taken school choice away from parents in this neighborhood,” said school committee member John Oliveira, who voted against the proposal. “This is fundamentally wrong.”

Mayor Jon Mitchell, who negotiated the outlines of what he described as an “out of the box” deal with officials from Alma del Mar and state Education Commissioner Jeff Riley, said existing state law on charter schools tied his hands. “For everyone that is disgusted with this, count me among you,” he said.

Alma del Mar originally sought approval from state education officials for 1,188 additional seats in New Bedford, a request that Mitchell described as irresponsible. He said the additional charter seats would have sucked millions of education dollars out of the New Bedford schools and plunged the city into financial receivership, forcing the closure of most police and fire stations and the layoff of hundreds of employees. “No exaggeration,” he said.

With little legal leverage on his side, Mitchell and officials from Alma del Mar, coaxed along by Riley, negotiated a deal limiting the expansion to just the 450 seats. When the state Board of Elementary and Secondary Education approved the deal, they also OK’d a fallback arrangement – if New Bedford and Alma del Mar were unable to make the 450-student deal work, Alma del Mar would be allowed to add 594 seats.

New Bedford Schools Superintendent Thomas Anderson said the addition of 450 seats at Alma del Mar was going to cost the school system about $4 million a year once all the students were enrolled after five years. Going to 594 seats, he said, would cost the system $8 million. The difference is enormous, he said. Giving up $4 million would mean no layoffs and no school closings, while giving up $8 million would result in layoffs and a series of other, potentially ugly choices.

“I don’t like it one bit,” Anderson said.

“To me it’s tantamount to outright blackmail by DESE,” said Oliveira, referring to the Department of Elementary and Secondary Education.

“The memorandum of understanding has been basically shoved down our throats,” said Christopher Cotter, the other school committee member who voted no.

Mitchell said it might feel good to vote no, but he said there was really no option for the city given the state of existing law on charter schools. “To my mind, the $4 million scenario is a far better alternative,” he said.

The mayor also said any charter that seeks to expand in New Bedford in the future will have to abide by the same conditions, which he said most charter operators would not agree to. “Most charter outfits would not have the guts to do it,” he said.

The memorandum of understanding spells out the responsibilities of the two parties and makes Riley the ultimate decision-maker if the two sides cannot agree on something. The school committee also voted 5-2 to recommend to the City Council that it approve a home rule petition that makes the necessary changes in state law to allow the deal to go forward. A vote to transfer the shuttered Kempton School to Alma del Mar at no cost was tabled until the home rule petition passes.

The home rule petition would grant an exemption from the current charter school law allowing the novel neighborhood charter school concept. The home rule petition would also grant New Bedford an exemption from state procurement and other laws that would bar New Bedford from turning over an abandoned school building to Alma del Mar at no cost.

The Massachusetts Teachers Association, which strongly opposes the New Bedford charter arrangement, had raised legal concerns about the school transfer earlier this week.

The special school committee meeting, held at the Keith Middle School, attracted about 30 members of the public. Only four members of the public testified – a lawyer representing the Massachusetts Teachers Association; Jack Bartholet, a US history teacher at the high school; Ricardo Rosa of the anti-charter group Save our Schools; and one other resident. No one spoke in favor of the deal with Alma del Mar.

Rosa said the school committee vote was a moral issue and not a choice of the lesser of two evils. “The lesser of two evils is still evil,” he said.

School Committee member Colleen Dawicki seemed glad to be putting the issue behind her. “This situation has pitted our community against each other,” she said.