THE CIVIL RIGHTS movement was pushed back to 1969 on Friday. The Treasury Department announced a reversal of a consistent 12-year policy of denying tax-exempt status to educational institutions that practice racial segregation. Citing the absence of clear statutory authority to withhold tax- exempt status, Treasury officials tossed this hot potato right to Congress, declaring that the benefits would be conferred unless Congress directs otherwise.

This is a deplorable step backward, and one that ignores not only existing laws but also a series of court decisions. The question has long been settled --or at least it had been--and if a good purpose is served by reopening it, no one has said what it is.

In fact, Congress has already acted. Title VI of the Civil Rights Act of 1964 specifically prohibits any kind of federal assistance to institutions practicing racial discrimination. Is tax-exempt status such a benefit? You bet it is. First of all, institutions that qualify are exempted from federal Social Security and unemployment taxes. Second, and more important, private contributions to such organizations are tax-deductible, so that gifts are in a real sense subsidized by the taxpayers. In both categories, the advantages that go with tax-exempt status can be measured in dollars and cents. Congress clearly meant to withhold them from segregated schools.

The courts have already spoken, too. Shortly after the 1964 act became law, civil rights groups in Mississippi sued to stop the government from granting tax-exempt status to Jim Crow schools. Even after the IRS conceded in 1970 that it "could no longer justify allowing tax-exempt status to private schools which practice racial discrimination," the Supreme Court affirmed a lower court's prohibition of the practice. In that case, Voit v. Green, the court affirmed Treasury's new policy as the only correct interpretation of the Internal Revenue Code. In light of this decision, it is difficult to understand Friday's announcement that tax authorities are powerless to apply a national interest test in these cases.

Finally, the Treasury's reversal of policy is wrong because it's too broad. To date, the Supreme Court has not decided the question of whether schools that discriminate can continue to enjoy tax-exempt status if that discrimination is the result of religious belief. This question was before the court until Friday, with the United States arguing, correctly, that while the government could not prohibit a religious belief that resulted in segregation, such belief need not be subsidized by the taxpayers through the granting of tax exemption. With its announcement Friday, Treasury not only reversed its position in the case of religious groups, it went much further, reinstating tax exemptions for all groups whether or not segregation was required by religious belief.

Now it's up to Congress. A number of members have already said they plan to reverse this new policy by clear and unequivocal statute. Support them.