By a one-vote margin, the Supreme Court ruled yesterday that the basic federal labor law doesn't require church-operated schools to bargain with unions representing their lay teachers.

For that reason, Chief Justice Warren E. Burger wrote in the opinion for the 5-to-4 majority, the court will not construe the law in a way that eventually might require the justices to resolve "difficult and sensitive questions" arising out of the Constitution's guarantees of freedom of religion.

For the dissenters, Justice William J. Brennan Jr. accused the majority of being "irresponsible" in avaiding resolution of the First Amendment issue "by a cavalier exercise" in interpreting the National Labor Relations Act "which succeeds only in defying congressional intent."

The ruling affirmed the 7th U.S. Circuit Court of Appeals in a case in which the National Labor Relations Board had asserted jurisdiction over lay faculy members at two groups of Roman Catholic high schools, one operated by the Catholic Bishop of Chicago and the other by the Diocese of Fort Wayne-South Bend, Ind.

As of 1978, Catholic schools across the county employed 114,000 lay teachers. Schools operated by other faiths employed tens of thousands more, but many such schools are exempt from NLRB jurisdiction simply because their faculties are small.

Bishop Thomas C. Kelly, general secretary of the United States Catholic Conference, welcomed the decision because it "reaffirms the right of church-related institutions to manage their own affairs free from government encroachment and control.

"It is important to note that this was the central issue," he said. The conference "was and remains committed to the right of employes of church-related institutions to organize and bargain collectively."

Albert Shanker, president of the American Federation of Teachers, AFL-CIO, said he will seek legislation to overcome the "narrow" decision. He added:

"The decision will not lead to the end of collective bargaining for parochial schools. However, instead of the orderly process of submitting petitions and the accompanying procedures under the [labor law], we can expect more strikes and other forms of confrontation in order to force parochial school employers into collective bargaining."

(In the Washington area, few attempts have been made by teachers at religious schools to organize unions, according to church, union and government officials.

(In Baltimore, teachers in the five archdiocesan high schools have been represented by a union since 1975, when it own an NLRB election.)

Yesterday's case began in 1974 and 1975 when one union petitioned the NLRB to represent lay teachers at two high schools in Chicago and another to represent their counterparts at five high schools in nearby Indiana.

Rejecting objections by the corporations that operate the schools, the NLRB said its policy was to decline jurisdiction in religiously sponsored organizations "only when they are completely religious, not just religiously associated." The agency then conducted elections. The unions won, but the schools, defying an NLRB order, refused to recognize the unions or to bargain.

Finally, in 1976, the board concluded that the schools had violated the law and ordered them to cease their unfair labor practices and to bargain collectively. The schools then successfully challenged the agency in the 7th Circuit.

The distinction between "completely religious" and merely "religiously associated," the appears court held, "provides no workable guide to the exercise of discretion." In addition, it said, the board's jurisdiction was forceclosed by the First Amendment guarantees: "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof..."

Chief Justice Burger recalled that in a 1976 case, the NLRB had said that regulation of labor relations doesn't violate the guarantees when it involves "a minimal intrusion" on religious conduct and is necessary to the fulfillment of the labor law's goals.

In doing so, he wrote for the court, the board "plainly recognized that intrusion into this area could run afoul of the religion clauses and hence preclude jurisdiction on constitutional grounds."

The reasoned this way: Congress has never clearly expressed an "affirmative intention" to have the law extend to lay teachers in church-operated schools. That being so, the question is whether NLRB jurisdiction presents a "significant risk that the First Amendment will be infringed." There is such a risk, one that arises even from the board's "very process of inquiry" into charges of unfair labor practices.

In the dissenting opinion, Justice Brennan, joined by Justices Byron R. White, Thurge White, Thurgood Marshall and Harry A. Blackmun, wrote that Burger's "cavalier" construction of the law "is plainly wrong in light of the act's language, its legislative history, and this court's precedents."

The law covers "all comployers not within... eight express exceptions," Brennan said. By amending it to add a new exception, he charged, the majority was engaging in law making. "This is a particularly transparent violation of the judicial role," he said. "The legislative history reveals that Congress itself considered and rejected a very similar amendment."