IT’S CLEAR WHY the teachers union in New York has gone to court to stop the city’s planned shutdown of failing schools and to block charter schools from using the public space. Jobs are in play, and the main mission of the union is, after all, to protect its members. What’s not clear is why the NAACP would join an effort to keep open schools that have failed miserably. Considering that it is mostly minority students who are affected, the NAACP’s action is almost incomprehensible.

The NAACP has joined in a lawsuit brought by the United Federation of Teachers that challenges New York’s plans to close 22 public schools and that would stop the expansion of 19 charter schools. It mirrors a lawsuit brought last year that halted the administration’s efforts to close 15 failing schools. The lawsuit contends the city has not done enough to help the schools succeed and that the formula in allocating common space such as auditoriums and gyms gives preferential treatment to charter students. NAACP officials told us that charter schools serve only a tiny number of students and that the NAACP is fighting for equality for all students.

The action, unlike last year, was filed late in the school year and would cause major disruption this fall; high school assignments have already been made, and the 7,000 students who won lotteries for coveted charter school spots would have to find alternative placements. That’s given rise to some speculation that the move is a ploy by the union in a fight with Mayor Michael Bloomberg over budget and contract issues.

Nonetheless, parents and students are caught in the middle, and their frustration was on display at a rally last week in Harlem. “My child cannot be told that she’s not going to get to go to her school in September,” said charter school parent Kathleen Kernivan. “I cannot look her in the eye, as a parent, and tell her, ‘Well, the problem is that this group of people that Mommy told you about during Black History Month, that did all those great things a long time ago – they want to stop you from doing great things.” The charter school that Ms. Kernivan’s child would attend, Leadership Prep Ocean Hill, is part of the Uncommon Schools system that has a record of success. It would replace a school where the vast majority of students remain below grade level in reading and math. P.S. 332 Charles H. Houston is in the bottom 1 percent for K-8 schools last year.

It’s not alone. According to figures released by school officials, the average English-language proficiency for elementary and middle schools set to be closed is 16 percent, compared with 42 percent citywide; in math proficiency, it is 19 percent vs. 53 percent.

“These figures are not something to brag about,” Schools Chancellor Dennis Walcott said as he argued that the union “should be with us.” That’s probably too much to expect, considering the union’s past intransigence. Surely, though, it’s not too much to hope for from an organization with a history of fighting for civil rights.