Vital social issues reach high court

A quiet referendum is under way in Washington, and its outcome will determine the fate of certain key Reagan administration initiatives in areas as diverse as civil rights and government regulation.

Only nine people will vote in this referendum, but those nine are the justices of the US Supreme Court, whose votes are often the last word on an issue.

The administration is proposing major shifts in national policy on abortion, affirmative action, government regulation, tax-exempt status for private schools , tuition tax credits, and the use of illegally obtained evidence. Each of these issues is now before the court.

Already since Oct. 4, when the new term began, the justices have heard oral arguments in cases in which the administration urges that the court give to state and national legislators more leeway to regulate abortion. And in another case already aired at the high court, the government is on record in favor of curtailing the power of the Internal Revenue Service to deny tax-exempt status to schools that discriminate against blacks.

Between New Year's Day and the end of oral arguments in late April, the justices will also hear the administration argue for a limit on the use of affirmative action - and for reversal of lower court rulings requiring more, not less, regulation of the auto and nuclear power industries.

In addition, the court will resolve a First Amendment challenge to a state tuition tax credit similar to the federal tax credit proposed by President Reagan. Critics charge that the federal proposal would, in effect, provide public support for private and parochial schools. And, in line with another administration proposal, the justices will consider making a major exception to the controversial exclusionary rule, which bans the use of illegally obtained evidence in court.

The affirmative action case comes from Boston, where black and Hispanic firemen and policemen - only recently hired as part of an intensive effort to increase minority representation in these departments - won a court order directing the city to ignore the usual rule of ''last hired, first fired'' when it had to make budget-dictated layoffs. To follow the rule, it was clear, would wipe out most of the minority group gains in these areas.

As a result of the judge's order, white firemen and policemen with far more seniority found themselves out of work, while black and Hispanic workers with less seniority held on to their jobs. The laid-off whites (since reinstated) went to court. The court will hear their arguments later this spring.

In the three Boston cases the Reagan administration agrees with the plaintiffs that the judge took the principle of affirmative action beyond permissible limits. It argues that in so doing he violated provisions of the 1964 Civil Rights Act, which was intended to protect senior employees from the adverse effects of efforts to remedy past discrimination.

Earlier this year, the Reagan administration asked Congress to create a ''good faith'' exception to the controversial exclusionary rule regarding evidence permissible in court. Since a Warren court decision in 1961, this rule has forbidden state and federal prosecutors to use evidence obtained in violation of a defendant's constitutional rights. A good-faith exception would permit the use of such evidence if the police who seized it thought they were acting legally.

In the case of Illinois v. Gates - to be argued a second time later this term - the justices will consider whether or not to create such an exception. This case arose after an Illinois couple was arrested on charges of drug possession. Their arrest followed after police searched their car and apartment and found marijuana in both locations. The police search warrant was based on a tip from an anonymous informer. The couple challenged that tip as inadequate basis for the warrant. State courts agreed and held that the drugs could not be used as evidence. The state contests exclusion of this evidence and will argue that because police acted in good faith, the evidence should be admitted in court.

The Reagan administration has asked Congress to approve a tuition tax credit for parents who pay tuition for their children's elementary and secondary schooling. Minnesota law permits parents to take a state income tax deduction of up to $700 for expenses related to schooling. Although some public school parents may benefit from this state tax deduction, those who challenge it argue that most of the benefit goes to parochial schools - and so the law violates the First Amendment ban on state action establishing religion.

Moving quickly to implement its campaign against government regulation, the Reagan administration in 1981 rescinded a rule requiring all cars made in the United States after September 1983 to have air bags or automatic seat belts. In 1982, however, a federal appeals court ordered the rule back into effect, declaring that the agency acted arbitrarily and capriciously in rescinding it.

Both the auto industry and the Reagan administration asked the justices to reverse the appeals court and permit rescision of the rule. Central to the cases is the question of whether an agency must have as much evidence to support withdrawing a regulation as it did to support issuing it in the first place.

In two other cases, the court is asked to reverse lower-court rulings that require more - not less - regulation of the nuclear power industry. Out of the Three Mile Island nuclear accident comes the case of Metropolitan Edison v. People Against Nuclear Energy, and Nuclear Regulatory Commission (NRC) v. PANE. The citizens' group won a ruling requiring the NRC to evaluate the psychological stress that would be imposed upon the community as a result of a decision to restart the unit at Three Mile Island not affected by the March 1979 accident. The NRC and the utility that operates the plant appealed, arguing that such an additional consideration is not necessary.

Growing national concern over the problem of nuclear waste is the backdrop for a case in which a lower court held inadequate the way the NRC considers this problem when licensing a new power plant. The NRC and several utilities are asking the court to discard this ruling, won by the Natural Resources Defense Council, which would require the NRC to deal with the problem anew each time it licensed a plant.