Schools Chancellor Joel Klein last week moved to exorcise one of the city’s most embarrassing racial quotas.

Klein went before a federal judge to demand the lifting of a race-driven regulatory structure imposed on Coney Island’s Mark Twain School in 1974.

It’s about time.

The Department of Education argued before US District Court Judge Jack Weinstein in Brooklyn, the same jurist who imposed the quota three decades ago, that it was no longer necessary.

More important, in light of a Supreme Court decision last spring that struck down quotas in Kentucky and Washington schools, the program seems clearly unconstitutional.

Morally, quotas are never defensible. But the circumstances leading to DOE’s actions underscore why the Mark Twain situation is particularly noxious.

The latest litigation was sparked by the magnet school’s rejection last year of the application of Nikita Rau, the 11-year-old daughter of Indian immigrants.

The school had already reached its pre-designated allotment of non-white students when it considered Rau’s application. Given the area’s shifting demographics, white students are now the “minority” students.

Rau scored well above the passing rate for whites on the school’s entrance exam, but below that for minorities – and was rejected.

Her parents sued the DOE.

The proper answer is obvious.

Weinstein should follow the clear advice of Supreme Court Chief Justice John Roberts, who stated in the majority opinion on the Kentucky and Washington cases: “The way to stop discrimination on the basis of race is to stop discriminating on the basis of race.”

Exactly.