The effort to enable communities like Dunwoody to create their own school systems says that Georgia is just fine with inescapable ghettos. It’s a return of bright dividing lines, like Ponce de Leon once was in Atlanta, with a photogenically multi-racial middle- and upper-class community whose members can reach for the American Dream on one side, and a mostly black, uniformly poor people who can’t on the other side.

It spits on the grave of Martin Luther King Jr.

That’s a strong statement. And it may seem unacceptably facile to frame the question as a racial issue. The new Dunwoody district would be about 50 percent non-white, after all. But neither this issue nor King’s legacy was solely about race. A separate Dunwoody school system — and the cascade of newly separated systems a proposed constitutional amendment creates — exacerbates a class problem that metro Atlanta too often ignores.

The amendment would allow any new city, and any municipality contiguous to a municipality created on or after Jan. 1, 2005, to form a new school system. Look at the proposed incorporation lines for Lakeside and Tucker. Then look at the plans Clarkston, Avondale Estates and Stone Mountain have for annexation. Clarkston goes north to the proposed Lakeside border. Stone Mountain has all of Smoke Rise on the table, connecting it to either Lakeside or Tucker. And Avondale Estates looks like it is coming really close to the Lakeside line.

Given the rejection of the Druid Hills independent cluster by the DeKalb County Board of Education a few weeks ago, I might expect its proponents to start thinking about incorporation.

Funding per student falls — if all of the possible cities choose their own districts — by about $1,500 per student, in my estimation. Perversely, it costs less to educate students in wealthy neighborhoods because administrative and special education costs tend to be lower. Dunwoody and the other new districts might pay about $8,000 per student, while the remaining DeKalb system would pay $11,500, given the number of special needs students, school resource officers and other costs. (I am not accounting for the obvious and unacceptable bloat in the DeKalb public school system. Call it $250 a student.)

The remaining two-thirds of the county would be covering two-thirds of the students on roughly one-third the tax base. It’s an implied tax increase of 100 percent or a service reduction of one half of the rest of the county’s school taxes.

Take the the average home in zip code 30083, an area in central DeKalb near Pine Lake. A typical home is worth about $70,000 now. (Compare that to averages closer to $175,000 in the areas looking to incorporate.) A homeowner there would pay about $300 a year more for school taxes on a $70,000 house. At current interest rates, the implied loss of net present value for a $300 extra annual cost is about $10,000.

Roughly two-thirds of the houses in zip code 30083 are under water. Take $10,000 out of their equity, and the figure becomes 85 percent. It means most people couldn’t afford to move without losing their house to foreclosure. Dunwoody’s move to separate its school system would trap everyone else in a place with underfunded, underperforming schools.

Harvard and Stanford released a study earlier this year looking at every metropolitan statistical area in the country, to see where someone born in poverty has the best and worst chances of rising to the top quintile of income. Atlanta placed dead last of America’s largest 50 metro areas, and 99th out of the top 100.

The key correlation wasn’t race. It was how much mixture people in poverty had with middle-class and wealthy families, how much time they spent working together, playing together, going to church together … or to school together. We live in one of the most economically segregated places in the country, with more concentrated wealth and concentrated poverty than almost any other metro area in America. A separate Dunwoody school system reinforces that problem, when we should be fighting it.

This isn’t exactly a black-white thing for me. Wealthy black families have exactly the same opportunities to educate their children that wealthy white families have. The evidence right now is that poor white families in metro Atlanta are just as screwed as poor black families in terms of being able to move up the economic ladder.

But most of the poor in DeKalb are black and Latino. And this move is going to have a disproportionate effect on people of color. I suspect that’s what it will come down to in court. As a city, Dunwoody can zone to keep low-income families from being able to move in. The net effect will be to push poorer (read: black) families into the now-further-weakened DeKalb school system.

I understand why Dunwoody wants it. The majority of the former school board was useless and potentially corrupt. But the new board is very strong. Kicking the legs out from under it now would be an unforgivable blow to the majority of the system’s students, just when things are looking up.