Wherever the Supreme Court's Jackson, Mich., decision eventually carries affirmative action, one thing is already crystal clear. All five opinions show that the Reagan administration, though winning the case, has lost its fight against "reverse discrimination."

The chief spear-carrier in that fight has been William Bradford Reynolds, head of the Justice Department's civil rights division. Reynolds has crusaded for "colorblindness," the legal standard fatefully bypassed 90 years ago in the Plessy case, giving the nation some 60 years of Jim Crow. It was and is an honorable standard, and Reynolds has defended it eloquently and seriously.

Under that austere standard, however, no "affirmative action" remedy for past racial wrongs could be countenanced except on a showing of specific personal injury. Oddly, the Reynolds standard of colorblindness was the liberal ideal for civil rights until the late 1960s. Beginning with the big-city riots, however, more aggressive plans for redressing the Jim Crow legacy began to emerge, including schemes involving "reverse discrimination," race consciousness and even racial quotas.

The era of colorblindness was too brief but will surely have a future. For even if reverse discrimination is justifiable as a temporary expedient, overindulgence could make civil-rights law into a checkerboard of capricious preferences.

But for the moment, the Jackson decision plainly says that the Supreme Court has not been sold on the Reynolds standard of colorblindness. And the reasons are clearly and persuasively spelled out in Justice Lewis Powell's plurality -- and controlling -- opinion.

It was Justice Powell who rescued the Bakke decision eight years ago from a choice between two troublesome extremes. His controlling opinion in that case neither endorsed the racial-quota system under which Alan Bakke had been excluded from a California state medical school in favor of less qualified minority applicants, nor did it rule race completely out of bounds in college admissions procedures, as presumably a strict "colorblind" standard would.

Powell's sensible compromise, defended with his usual lucidity and thoughtfulness, was that race might be considered -- but only as one of many balanced admissions criteria. He cited the example of Harvard College, which gives weight, though not decisively, to race even as it gives weight to geography, grades and test scores.

Once again, in another important affirmative-action decision, the court has found a center of gravity and agreement in Powell. He leaves no doubt of his distaste for racial categories and abhors the idea of burdening innocent persons for the sake of transcendent social goals.

But he recognizes, as do all the justices with various degrees of enthusiasm, that this must sometimes be done. "As part of this nation's dedication to eradicating racial discrimination," he writes, "innocent persons may be called upon to bear some of the burden of the remedy." Powell, to his credit, declines to disguise or prettify this painful fact -- and it is painful.

The question, always, is what pain, with what justification, an innocent party might be called upon to bear for a larger public policy. What decided Powell against the Jackson plan -- a layoff scheme for schoolteachers that violated seniority custom to preserve minority faculty ratios -- was not that it took account of race. It was that the plan (entered into under the pressure of racial unrest between the Jackson school board and the teachers union) was not clearly based on an actual history of discrimination. A vague history of "societal discrimination," though no one would deny it, is not enough to justify placing such a burden on people who happen to be the wrong color. Powell also noted, sensibly, that layoffs are far more disruptive to careers than discrimination in hiring plans.

Powell's emergence as the consensus voice of the court perhaps makes the medicine a bit more palatable to stern advocates of strict colorblindness. He certainly cannot be suspected of tampering lightly with basic constitutional principles.

And anyway, this thorny issue is far from conclusively settled. The defects of color-conscious remedies for racial discrimination are many and obvious, while the only clear defect of colorblindness is that it works uncertainly and slowly to leaven entrenched institutional discrimination. Otherwise, it remains an unassailable principle of justice.