Justices Further Resist Finding Right to Sue

But other justices said such comments could not be reconciled with the Supreme Court's history, both distant and more recent.

In 1969, it found in Sullivan v. Little Hunting Park that retaliation was covered by another federal law derived from the 1866 act, even though the word itself was not specifically mentioned. Neither is the right to sue, Justice Stephen G. Breyer noted last week, but the court recognized that it was necessary "to make the statute effective."

Added Justice Ruth Bader Ginsburg: "Wouldn't it be odd to take these twin measures" -- the one decided in Sullivan and the other relied upon by Humphries -- "and say one includes retaliation and the other doesn't?"

Less than three years ago, the court voted 5 to 4 to find that Title IX protected a basketball coach who complained about sex discrimination, even though reprisals are not mentioned in the act.

"Retaliation against a person because that person has complained of sex discrimination is another form of intentional sex discrimination," wrote Justice Sandra Day O'Connor in her last full term on the court.

That decision was rooted in the Sullivan opinion, which was decided in what Scalia called the "bad old days" when the court was "inferring causes of action all over the place."

Roberts picked up the thread in questioning how the court should honor stare decisis, the idea that the stability of the law depends on the court upholding its precedents.

" Sullivan would not have come out the same way today," Roberts said during arguments in the Humphries case. "So if you're concerned about stare decisis which body of law do you give effect to, the Sullivan case or our more recent cases on how to read statutes?"

Solicitor General Paul D. Clement, who represented the Bush administration supporting Humphries, told the justices that they have already settled that there is an implied cause of action. "We are simply asking you to interpret the scope" of what has already been granted, he said.

Justice Samuel A. Alito Jr., who replaced O'Connor on the court, asked questions that did not indicate how he will decide the case.

Eric S. Dreiband, a Washington lawyer and former general counsel to the Equal Employment Opportunity Commission nominated by President Bush, said he believes the court's precedents "almost compelled a result in favor of Humphries."

A decision otherwise, he said, would mark another significant shift in the court's jurisprudence.