Give Eric Holder credit for cognitive racial dissonance. On nearly the same day the Attorney General spoke in Washington to honor the 50th anniversary of Martin Luther King Jr.'s "I have a dream" speech, his Justice Department sued to block the educational dreams of minority children in Louisiana.

Late last week, Justice asked a federal court to stop 34 school districts in the Pelican State from handing out private-school vouchers so kids can escape failing public schools. Mr. Holder's lawyers claim the voucher program appears "to impede the desegregation progress" required under federal law. Justice provides little evidence to support this claim, but there couldn't be a clearer expression of how the civil-rights establishment is locked in a 1950s time warp.

Passed in 2012, Louisiana's state-wide program guarantees a voucher to students from families with incomes below 250% of poverty and who attend schools graded C or below. The point is to let kids escape the segregation of failed schools, and about 90% of the beneficiaries are black.

But Justice is more worried about the complexion of the schools' student body than their manifest failure to educate. During the 2012-13 school year, about 10% of voucher recipients came from 22 districts that remain under desegregation orders from 50 or so years ago.

For example, says the complaint, in several of those 22 districts "the voucher recipients were in the racial minority at the public school they attended before receiving the voucher." In other words, Justice is claiming that the voucher program may be illegal because minority kids made their failing public schools more white by leaving those schools to go to better private schools.