PRESIDENT REAGAN would like to have it

both ways. Last week he hoped to please the people running segregated schools by reversing longstanding policy and exempting them from taxes. But, discovering the opposition to that misguided decision to be stronger than he had anticipated, he now says that he will propose legislation to revoke the exemption in the future. But he has missed the right answer: to leave the original rule--no tax exemption for racially segregated institutions--in place.

Over the years, the segregated schools had managed to persuade themselves that the refusal of exemption had no basis but an off-the-cuff decision by a hostile bureaucracy in the Internal Revenue Service. That is an utter myth, but a few people perpetuated it as a political cause to which, unfortunately, Mr. Reagan responded. The complaint was that Congress had never addressed the issue. That's wrong. Congress set the policy in the 1964 Civil Rights Act and when the IRS subsequently applied it to these schools the Supreme Court upheld it as a correct reading of the law.

Mr. Reagan evidently hopes to placate everybody by claiming that the rule was not valid in the past, but that congressional action, with his support, will now make it so. This awkward maneuver is unlikely to gratify the segregated schools, as they see their cherished exemptions snatched away again. Nor does it deserve anything but reproach from that very large majority of Americans who deplore racial segregation and object to this show of conferring on it, however briefly, the degree of federal approval that the exemption implies.

Perhaps the benefits to the segregated schools will be more substantial than a few months' exemption suggests. These institutions will apparently be in a position to claim repayment, with interest, of all the taxes that the government has legitimately collected from them since 1970.

Congress seems ready to act promptly. For the future, the reimposition of the rule seems very probable. But it is truly unfortunate that Mr. Reagan should have chosen to reopen a question that most people considered to have been closed, decently and properly, long ago. Perhaps the only surprising thing about the force and vehemence of the reaction to Mr. Reagan's original move is that Mr. Reagan should have been surprised by it. In this deplorable affair, the administration has displayed a lack of courage of its lack of conviction.