The head of Lusher Charter School and her administrative team have come out swinging against the push to unionize teachers at the high-performing New Orleans magnet school, calling the move a divisive power grab that won’t benefit students.

It’s the first big showdown between school managers and the union that used to represent local educators before it was sidelined by the state takeover of most local schools that followed Hurricane Katrina.

In the past few years, the union, the United Teachers of New Orleans, has tried to make new inroads, helped along by nearly $500,000 from its national parent organization, records show.

Among New Orleans charter schools — which operate autonomously and typically eschew unions — two other schools have more or less willingly allowed their teachers to unionize.

But administrators at Lusher are apparently determined to fend off the new union push.

Their letter, signed by CEO Kathy Riedlinger and five other administrators on Friday, came a day after Lusher’s board pledged to stay neutral on the issue — warning teachers not to employ coercion to try to get their colleagues to endorse the union but saying the board would remain above the fray.

Riedlinger and her top deputies, on the other hand, were emphatic.

“In our opinion, introducing a union into Lusher will negatively affect direct communication of administration with teachers, add an additional layer of bureaucracy and feed an adversarial tone that has not previously been part of the atmosphere at Lusher,” their letter said.

The administrators also expressed concern over “the union’s history with, and opposition to, charter schools.” Further, they said, “the union side has interests other than the well-being of Lusher students, like building power through numbers.”

The question of whether Lusher’s staff should join the United Teachers of New Orleans has divided the school’s community since January or perhaps earlier, when a group of pro-union teachers began distributing a petition in favor of the idea.

The anti-union camp has accused union supporters of acting secretively and making too much of trivial complaints about how the school is run.

Union proponents, on the other hand, say a schoolwide culture of fear has made secrecy necessary and claim a union will help give teachers more of a voice.

Members of the school’s board faced a tricky decision. They have heard an earful from both sides. Organizers say more than 60 percent of the faculty have signed a petition in favor of the union, but a handful of the signers then backed out. By a close vote, board members declined last month to voluntarily recognize the group.

But that only cleared the way for the National Labor Relations Board to oversee a secret ballot among teachers at Lusher, likely before the school year ends. The board has said it will remain neutral until that vote.

It is the first time a marked division in a local unionization push has played out so publicly; efforts at other schools secured the support of a much greater percentage of faculty.

Teachers at Morris Jeff Community School and Benjamin Franklin High School already have unionized. Those at the International High School of New Orleans also have asked that school’s board to consider recognizing the union.

The national American Federation of Teachers has played a big role in these organizing efforts, funneling more than $491,000 to the “AFT/UTNO Organizing Project” — a campaign specifically directed at New Orleans charter schools — between July 1, 2013, and June 30, 2015, federal records show.

Senior national representative Audra George, who has become a staple at local charter board meetings, earned $234,090 in 2014-15.

AFT also paid almost $650,000 to help another local affiliate, the Jefferson Federation of Teachers, clinch a favorable Jefferson Parish School Board majority in 2014. Parish business leaders, seeking to shut the union out, put up $400,000 over two years but were outspent.

The AFT’s position on charter schools is that they tend to empower management at the expense of teachers, who are left without long-term contracts or any formal means of influencing decision-making.

Local teachers who have pushed for unions don’t see them as antithetical to charter schools, but as a necessary corrective. And they don’t see the bogeyman in the AFT that some charter advocates do.

Lusher high school math teacher Jerome White said the notion that he or his colleagues are pawns in the AFT’s organizing plans is false. “This started not with an UTNO person coming in and soliciting us, but as conversations among Lusher teachers,” he said.

He called the insinuation that union supporters care less about children insulting. “We deserve the benefit of the doubt we are not doing this with ill intentions,” White said.

Follow Jessica Williams on Twitter, @jwilliamsNOLA.