A RISING intolerance for bigotry in the past few years has blanketed the country with new public laws and campus codes against speech and action motivated by bias.A case to be heard Dec. 4 before the Supreme Court could provide a test for how far these codes can go in outlawing bias before they trample on free-speech rights. In the early morning hours of a June night in 1990, a group of young white men went through the fence and into the front yard of the only black family living in a working-class neighborhood of St. Paul, Minn. There they planted a cross made of two legs of a broken chair, wrapped in terry cloth and doused with paint thinner, and set it on fire. The family, Russ and Laura Jones and their five children, had already had their tires slashed, a car window broken, and their children called racial epithets in front of their house. But the cross-burning was the strongest message yet, with a long and clear history as a racist threat to "get out or else." The police soon arrested a 17-year-old youth as a participant and chief instigator of the crime. Even his own attorney argues that he should be punished for vandalism, trespassing, or the implicit threat of violence in his act. But the city of St. Paul prosecuted him under one of the nation's most sweeping hate-speech bans. The 1982 city ordinance bars the placement of any symbol "which one knows or has reasonable grounds to know arouses anger, alarm, or resentment in others on the basis of race, color, creed, religion, or gender." As written, the ordinance could ban burning a cross on one's own yard because a neighbor resented it. A trial judge dismissed the case before trying it, ruling that the ordinance was too broad and conflicted with the constitutional right to free speech. The Minnesota Supreme Court reversed that dismissal, however. It saved the ordinance by giving it a very narrow interpretation - reading it to ban only "fighting words" intended and likely to produce "imminent lawless action." If the US Supreme Court accepts this narrow reading of the ordinance by the state court, then its decision is unlikely to define new areas of free-speech law - although it might clarify what constitutes fighting words. But if it makes a decision on the ordinance as it is written, then it may shift the boundaries of what speech is protected under the Constitution. Is hate speech treated with the same full protections as other speech under the law? Or can a special exception be made, as for obscenity, so that hate speech can be banned? "That would be a radical retreat from the rulings of the last 20 years," says Rodney Smolla, a law professor at William and Mary College law school and a specialist in free-speech issues. The case enters an atmosphere charged with controversy over the orthodoxies of the cultural left - dubbed political correctness. The free-speech consensus has eroded substantially. A decade ago, says Mr. Smolla, few legal scholars questioned that Nazi and Ku Klux Klan expressions of racism were protected under the First Amendment. Now, in academic circles, these questions are "totally at play." No evidence has yet surfaced, however, that the current Supreme Court seeks a major retreat from the broad, liberal protection of free-speech established under the Warren court. The only changes in free-speech doctrine have come at the margins. In a case last year that upheld regulations banning clinics receiving federal funds from discussing abortion, for example, the court allowed restrictions on what it deemed government-sponsored speech. The Supreme Court held that cross-burning could be Constitutionally protected as a free expression in 1969. In 1989, the court held 5 to 4 that flag-burning could also be protected speech. Two members of the majority in the flag-burning case, however, have since retired, casting some doubt on the court's current disposition. The St. Paul cross burning was different, argues Michael Lieberman, Washington counsel to the Anti-Defamation League of B'nai B'rith. Unlike burning a cross or a flag on public property or on the land of a participant, this incident was a threat aimed clearly and directly at one family and in their own yard. The threat was not hate speech, but hate-driven threat of assault, he says. Some legal thinkers, such as Richard Delgado, scholar in residence at Washington and Lee University, would like the courts to eventually ban speech that degrades groups of people, such as racial minorities or homosexuals, who are subordinated to the dominant social group. "Language," he argues, "is a subordinating tool, a reminder that you don't belong." He does not expect the current court to move very far toward such a view, however.