The Supreme Court's most recent ruling on racial policy deserves the title Stevie Smith gave to a volume of her poems: "Not Waving But Drowning." In the 5-4 decision, the justices produced five opinions, and no four justices joined fully in any one of them. So tangled are the justices in the hairs they have split about reverse discrimination, or affirmative action, that their rulings send ambiguous signals that must be amplified by subsequent decisions generated by the ambiguities.

Deciphering the court's most recent signal is doubly difficult because, although it is welcomed by advocates of affirmative action, the decision overturns a lower court's endorsement of an affirmative-action plan. The Jackson, Mich., school board negotiated with the teachers union a plan stipulating that if layoffs became necessary, teachers with most seniority would be retained, except -- hear, now, the contemporary language of civil rights -- "except that at no time will there be a greater percentage of minority personnel laid off than the current percentage of minority personnel employed at the time of the layoff." That is, a race quota would supersede a colorblind seniority system.

Layoffs came, and white teachers with seniority sued. They won in the Supreme Court, but their victory was actually a defeat for opponents of "race-conscious" policies.

True, the court overturned a lower court's ruling that the mere fact of "societal discrimination," or the goal of creating "role models" for minority children, justifies policies of racial preferences. However, all nine of the justices now seem opposed to the Reagan administration's position. Its position is that the constitutional guarantee of "equal protection" of the law requires public policy to be colorblind, except when correcting the effects of particular acts of discrimination against identified individual victims. In the Jackson case, the justices busied themselves producing guidelines for constitutionally permissible "race-conscious" policies. Such guidelines constitute an invitation to devise such policies.

Justice Powell's plurality opinion said it can be constitutionally permissible to injure innocent persons -- persons not guilty of discrimination -- by racial preference programs that are "part of this nation's dedication to eradicating racial discrimination." Presumably he means eradicating the effects of discrimination. Because there can hardly be clear criteria for deciding when that has been achieved, there can be no clear criteria for terminating "race-conscious" programs.

The coalition-building politics of a nine-person group can have many permutations, but the crucial opinion in this case was that of the Reagan appointee, Justice Sandra O'Connor. She said that despite appearances, the court is "in accord" on certain "core principles," including these: valid affirmative action need not be limited to correcting "specific instances of individual discrimination"; and a public employer may implement remedial affirmative action that does not do "disproportionate" harm to the interests of the innocent or "unnecessarily" trammel their rights.

What constitutes "proportionate" harm and "necessary" trammeling? Stay tuned for the cases this case will cause.

One case may bounce right back from Jackson, Mich. Four dissenting justices (Blackmun, Brennan, Marshall, Stevens) said the Jackson plan was constitutional. Powell made much of the fact that racial quotas in layoffs are more burdensome to innocent victims than are racial hiring quotas, the burdens of which are "diffused" among society generally. O'Connor, in the middle, intimated that a race-conscious policy might pass muster with her if it linked "the percentage of qualified blacks on a school's teaching staff and the percentage of qualified minorities in the relevant the community's labor pool." Jackson may consider that an invitation to try again.

However confusing the welter of opinions in this case is, the case has semi-decisively made something somewhat clear: the court will circumscribe but will never proscribe reverse discrimination.

The court has reached what O'Connor calls ''a degree of unanimity.'' Obliquely and confusingly but unmistakably, the court has carved out an exception to the central principle of liberal democracy. That principle is that rights inhere in individuals, not in favored groups. So the civil-rights movement will continue to concentrate on constructing a racial spoils system, getting government to accord special rights to certain minorities.

What is the signal from the court? The court is not waving, it is drowning. It is drowning in the work it cannot stop making for itself. This is the work of manufacturing criteria for judging constitutionally sanitary "race-conscious" policies, the work of reconciling "equal protection" with reverse discrimination.