There's been an empty seat on the Board of Education since South Los Angeles representative Marguerite Poindexter LaMotte died unexpectedly last month. On Tuesday, board members are expected to decide how to fill her spot.

Their options are straightforward: The board can appoint someone to fill out the remaining 18 months of LaMotte's term. Or it can leave the spot vacant and let voters pick her replacement in an election several months from now.

Nothing's ever that simple, though, in this fractured school system; politics and personal agendas have already begun to intrude.

LaMotte was the school board's only black representative. Her district includes some of the city's poorest neighborhoods and lowest-scoring schools.

A retired high school principal, LaMotte won all three of her elections with teachers union support. She was more firebrand than brain trust; an old-school educator with disdain for charter schools and corporate-led reforms, and tough-love passion for her "babies," particularly black students.

LaMotte was the only board member who gave Supt. John Deasy an "unfavorable" job rating — instead of "satisfactory" — in his evaluation last fall.

She may not have been a leader on the board, but her voice was hard to ignore. The superintendent has a chance now to get rid of that pebble in his shoe.

So I wasn't surprised to hear that Deasy is soliciting black civic leaders to form an advisory committee to deal with issues in LaMotte's South Los Angeles district. I expect they will be folks who — unlike LaMotte — support Deasy's reforms.

The superintendent isn't the only one with a stake in her replacement.

The teachers union stands to lose if the balance of power on the school board shifts. I expect behind-the-scenes maneuvering to advance a candidate that's as reliable a supporter of union positions as LaMotte had been.

Black political leaders see possibilities in a new board member that go beyond school safety and test scores. The school board has been a traditional launching pad for ambitious politicos. I predict that politicians will soon be grooming LaMotte's prospective successors and planning their election night parties.

Then there are the community groups that have become a potent force that's helped steer the district's agenda. Groups like the Community Coalition forced the district to reduce student suspensions, helped pass last year's ballot measure preserving school funding, and persuaded skeptics to support the iPad project, despite its bungled rollout.

"We had young people walking precincts for Proposition 30," said the coalition's Executive Director Marqueece Harris-Dawson. Now, with LaMotte gone, they are concerned that their schools won't have a vote when the money is divvied up.

Expect to see them at Tuesday's board meeting, lined up alongside the politicians, civic leaders and union advocates.

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According to my colleague Howard Blume, the school board seems inclined to leave LaMotte's seat open and hold an election; at the earliest, this spring, at the latest, in November.

It's a nice idea, in theory: Let the voters decide.

Los Angeles County Supervisor Mark Ridley-Thomas, who lives in LaMotte's district, said: "I'm not about to let someone elected by other parts of the city choose who will represent my interests. The only legitimate, fair, time-tested way to do that is through an election process."

But that's a bad idea in practice. It risks shortchanging vulnerable children at a pivotal time.

"We can't wait until April or June to represent them, when there are so many critical decisions the board is making now," said Rep. Karen Bass (D-Los Angeles), who initially supported an election.