CAN America no longer afford the First Amendment? Or is the First Amendment more important today than ever before?These stark choices are implied in the debate raging in the United States over society's proper response to an unprecedented climate of offensive and perhaps harmful expression. "The media and the pornography industry are working overtime to ensure that our society is filled with sexual messages," says Joanne Masokowski, founder of Protect the Children Resource Center in Concord, Calif. The controversy centers most around two kinds of expression: obscenity and hate speech. These are the cutting-edge issues of free speech in America. * Obscenity. Movies, television, heavy metal and rap music, and printed pornography - popular culture is filled with it. Pop stars like Madonna, the rap group 2 Live Crew, and comedian Andrew Dice Clay spew forth degrading words and employ sexually suggestive gestures in their acts. True "obscenity" as defined by the Supreme Court enjoys no First Amendment protection, since the justices have said that child pornography and hard-core porn that meets the court's obscenity test aren't "speech." State and local governments actively prosecute producers and distributors of obscene materials, says Deen Kaplan of the National Coalition Against Pornography in Cincinnati. More than 90 percent of the pornography cases brought to juries result in guilty verdicts, Mr. Kaplan says. Beyond legally proscribed obscenity, however, is a vast realm of soft-core porn and other sexually-oriented forms of speech that government can't outlaw. Government shouldn't wield scissors in a free society, says Rodney A. Smolla, director of the Institute of Bill of Rights Law at William & Mary Law School and an opponent of censorship. Professor Smolla notes that many artistic works which, whether one approves of them or not, have made important statements and were greeted with indignant calls for suppression - from James Joyce's "Ulysses" to the recent film "The Last Temptation of Christ." Smolla also worries about the "hidden political agenda" in much censorship. "It's no coincidence that censorship is often targeted against society's fringe groups," he says. Defenders of even the most extreme rap lyrics, for instance, contend that the music is an authentic expression of the powerlessness and rage felt by many blacks, and thus is politically significant speech deserving of First Amendment protection. The libertarian's customary remedy for people offended by obscene speech is simply to turn away from it; one isn't forced to read Hustler or view an exhibit of Robert Mapplethorpe photographs, they say. Yet turning away is becoming increasingly difficult in a society inundated with sexual imagery. And many parents are particularly alarmed about the exposure of children to sexually explicit expression through recordings, cable TV, and dial-porn. Thus, calls are rising for such private-sector measures as warning labels on recordings and self-censorship by film and TV producers. An emerging element in the debate over obscenity that could alter its terms is the question of the harm it causes. Women's and children's groups are intensifying research into possible links between pornography and deviant behavior. Mr. Kaplan of the National Coalition Against Pornography says researchers are finding high statistical correlations between porn and sex crimes. If their data come to be broadly accepted, some sexually-oriented materials currently protected as speech could be viewed more as harmful substances subject to government regulation. * Hate speech: Invective against minorities, women, Jews, homosexuals, and other victims of bigotry. Manifestations of bigotry are rising throughout American culture, but intolerance has become a cause of special alarm on college campuses, where incidents of bigotry have skyrocketed in recent years. "Acts of prejudice and bigoted violence are increasing around the country, both in frequency and intensity," says Robert Purvis of the National Institute Against Prejudice and Violence in Baltimore. Many colleges, intended to be gardens of rational discourse, paradoxically have become seedbeds of intolerance. In part because of widening diversity in the student-age population, and in part because of schools' affirmative-action programs, students of varying backgrounds are thrown together more intensely than in the greater society. An article in Time magazine last year noted that most campuses "are vastly more heterogeneous than most high schools and neighborhoods. Under such hermetic conditions, the chemistry has proved volatile and relations explosive." In a study last year entitled "Hate in the Ivory Tower," the Washington organization People for the American Way reported that, of 128 colleges responding to a survey, "57 percent acknowledged that intolerance posed a problem on campus." The hate is expressed in racist, sexist, and homophobic graffiti on dorm walls, exchanges of epithets between students, and even physical harassment. To curb expressions of intolerance, many colleges have adopted speech and conduct codes banning, in the words of one such code, "slurs or epithets based on race, sex, ethnic origin, disability, religion, or sexual orientation." In February, a Brown University student was expelled for drunkenly shouting racial and anti-Semitic epithets. However, the codes have been widely criticized as violating the First Amendment. And courts in Michigan and Wisconsin have ruled that the codes established by the state universities were unconstitutionally broad and vague. (In a case that could affect campus codes, the US Supreme Court this year will decide whether the First Amendment protects a Minnesota youth who burned a cross outside a black family's home from being prosecuted under a St. Paul hate-speech ordinance.) "If you can't have open, even raunchy debate on a college campus, where can you have it?" asks Sandy Horwitt of People for the American Way. In its 1990 study People for the American Way opposed campus speech codes as ineffectual and infringing on fundamental free-speech rights. The answer to bigotry on campus, say critics of speech codes ranging from the liberal American Civil Liberties Union to Chester Finn, an Education Department official in the Reagan administration, is not censorship, but rather more and better speech aimed to open closed minds, rebut ignorance, and increase tolerance. But proponents of campus codes, including representatives of many women's and minority groups, counter that true learning cannot go on in an environment poisoned by hate. In the absence of minimum standards of civil and respectful behavior on campus, they say, many victims of bigotry will feel intimidated and will withdraw from the intellectual and social life of the school. Advocates of curbs on bigoted expression say that as America becomes a more multiethnic and urbanized society, the potential for incendiary social friction grows apace. A society has a right to defend itself from verbal arsonists and bomb throwers, they insist, even if the cost is some restraint on free speech. William & Mary's Smolla acknowledges that "virtually every other country in the world bans hate speech." But the law professor, pointing to ethnic strife in the Soviet Union, Yugoslavia, and elsewhere throughout Europe, says, "Official bans on hate speech seem to have done less to eliminate intolerance in those countries than free speech has accomplished in the United States."