The Justice Department cites two public schools to illustrate its concerns. Five white students used scholarships to leave one, "reinforcing the racial identity of the school as a black school." In another, the exit of six black students made a "white school" whiter.
This is racial bean-counting at its worst. Jason Bedrick, who studies education policy at the libertarian Cato Institute, calculates that the first school went from 29.6 percent to 28.9 percent white. The second went from 30.1 percent to 29.2 percent black. These are trivial changes.
The Justice Department is also measuring school segregation in a perverse way. It treats a school as integrated when it matches the racial composition of the school district. Yet the districts are themselves segregated - and tying school attendance to residency makes that segregation worse.
Neighborhoods with good public schools have higher property values, which makes it harder for poor black families to move into them. Americans who have enough money exercise school choice when they buy their homes.
Greg Forster, a researcher who favors school choice, addresses the measurement problem by comparing schools' racial makeup to that of their metropolitan areas. He points out that seven studies have found that school choice promotes racial integration - measured correctly - while one found it has no impact. No study has found that it promotes segregation.
It seems likely that school choice reduces segregation in large part by breaking the link between residency and schooling. That effect would, however, be at best invisible to the counters at the Justice Department. They might even see it as a step backward, given the way they count.
Forster also found that of the 12 best studies on school choice and educational outcomes, 11 found positive effects and one found no effect. The racial integration of schools, while a good thing, is not as important as getting students to learn more.
A policy that showed educational promise but also had the side effect of decreasing integration would be worth pursuing - and so far we have little reason to think that school choice involves any such tradeoff.
If the Obama administration isn't willing to embrace school choice itself, it should at least quit trying to squash it in the states and cities that are.
Ponnuru is a Bloomberg View columnist, a visiting fellow at the American Enterprise Institute and a senior editor at National Review.