The Supreme Court yesterday heard arguments on a New Jersey law requiring a moment of silence in public schools, but there were indications that the court will be unable to make a definitive ruling on the law's constitutionality.

The law, similar to ones passed in nearly half of the states, was enacted in December 1982 after the state Senate and General Assembly overrode a veto by Gov. Thomas H. Kean (R). A group of schoolchildren and their parents challenged the law. The attorney general and the governor decided not to contest the matter in court, but Alan J. Karcher, speaker of the Assembly, and Senate President Carmen A. Orechio intervened to argue for the law's constitutionality.

But both men lost their leadership positions after the 1985 elections, and neither the executive branch nor the legislative leadership wants to pursue the matter.

Yesterday's argument was largely devoted to an intricate discussion of whether Karcher and Orechio have legal standing in court on the issue.

The law, which never took effect, simply "provides an accommodation for those students who want to use a moment of silence for prayer" and was not intended to require prayer, argued former solicitor general Rex E. Lee, representing the two legislators.

But Norman L. Cantor, representing children and parents who challenged the law, said there was ample evidence at a five-day trial for the trial judge to conclude that "the asserted secular purpose was a sham."

The judge struck down the law in 1983, saying it was an unconstitutional effort to reintroduce organized prayer into the schools in violation of a 1962 Supreme Court ruling. A federal appeals court upheld the decision.

Cantor argued that Karcher and Orechio, as members of the legislature, cannot speak for it and have no legal right to pursue the appeal. "The real party {in the lower court rulings} was the legislature and that legislature has decided not to continue the appeal." Karcher and Orechio, he said, cannot do so on their own.

Justices William J. Brennan Jr., Thurgood Marshall, Sandra Day O'Connor and Antonin Scalia questioned Lee closely on his argument that the legislators could press their appeal. Marshall and Scalia indicated doubts that the lawmakers could have appealed even if they had retained their leadership posts.

The matter should have ended once the executive branch declined to pursue the case, Marshall said; otherwise, the legislature would be exercising executive branch powers.

If the legislature can intervene to press lawsuits, "why can't the legislature execute the law when the executive refuses to do so?" asked Scalia.

The court in 1985 struck down 6 to 3 an Alabama law requiring a moment of silence for "meditation or prayer," saying that the law was passed as a means of circumventing the court's 1962 ruling. But a majority of justices in that case said they would likely uphold a law that did not mention prayer or that was not intended to promote religion.

Justice John Paul Stevens, who wrote the 1985 decision, indicated yesterday that he felt the New Jersey silence period may be acceptable because it appeared to be required before the start of the school day.

The New Jersey law requires teachers to "permit students to observe a one-minute period of silence to be used solely at the discretion of the individual student, before the opening exercises of each school day for quiet and private contemplation or introspection."

A ruling in the case, Karcher v. May, is expected by the end of the court's term next spring.