Several thousand demonstrators march in Berkeley, Calif., on Aug. 27 in response to a planned right-wing protest that raised concerns of violence and triggered a massive police presence. (Josh Edelson/AP)

Alan M. Dershowitz is an emeritus professor of law at Harvard University and the author of "Trumped Up: How Criminalization of Political Differences Endangers Democracy."

When I was a student during the days of McCarthyism, a book arguing for the censorship of extremist hate speech would have been titled "Must We Defend Communists?" Many of the arguments made by Richard Delgado and Jean Stefancic in "Must We Defend Nazis?" are similar to those that would have been made in my hypothetical book: Free speech is not absolute; it must be balanced against other societal values; much harm can come from communism; communists don't support our free speech, so why should we support theirs; communism is evil, and there is no good reason to defend evil speech; communist propaganda lies at the periphery of the First Amendment, not at its core; communist speech incites violence; those who defend communist speech are complicit in the evils of communism.

"Must We Defend Nazis?" argues that "the ACLU and conservative bigots are hand in glove"; those advocates of free speech, "including First Amendment purists," who "defend" the right to tell ethnic jokes and hurl racial epithets are guilty "as well." Hate speech incites violence.

Now the right shoe of censorship is on the left foot. Those who seek to ban what they call hate speech are on the hard left, particularly at universities. Those who seek to defend free speech are accused of bigotry. This book makes the case for race-based affirmative action in the context of free speech. It calls for special rules designed to protect minorities, especially racial minorities. It bases its argument on the following highly questionable proposition: "There is no correlate — no analog — for hate speech directed toward whites. . . . There is nothing comparably damaging that whites have to undergo. The word 'honky' is more a badge of respect than a put-down. 'Cracker,' although disrespectful, still implies power, as does 'redneck.' " Tell that to a first-generation college freshman from the Ozarks who is called by those names.

On today's campuses, identity politics creates an atmosphere in which grievances abound. Some African Americans demand separate but equal "safe" dormitories and eating areas, as well as protection against micro-aggressions and white privilege. Some Asian Americans argue that race-based affirmative action programs discriminate against Asian applicants. Some Jewish students point to anti-Israel hate speech, including accusations that they — American Jewish students — are complicit in genocide, apartheid and war crimes. Some Muslim students claim that the very presence of Zionists on campus makes them feel unsafe. Some Christian students say their religious beliefs, particularly regarding abortion and same-sex marriage, are mocked and belittled. Some gay, lesbian and transgender students feel marginalized in a hetero-dominant culture. Some women believe that campuses promote "rape culture" and that allowing anti-abortion voices to be heard exacerbates the view that men control women's bodies.

These voices, especially those to whom the authors of this book would accord special protection, are heard loudly and clearly by university administrators. No one on the hard left is censored these days. The same cannot be said for the hard right or sometimes even the center right. Zionist speakers are routinely shouted down and prevented from speaking by those who regard pro-Israel speech as hate speech. I know, because I have been shouted down and prevented from completing my remarks, despite my support for a two-state solution and my opposition to Israel's settlement policies.

Once a university travels down the road to censoring some speech, it becomes a player in the never-ending zero-sum game. Is Zionist speech anti-Muslim? Is anti-Zionist speech anti-Jewish? Is Christian fundamentalist speech anti-gay or anti-women? Is pro-gay-marriage or pro-abortion speech anti-Christian? Are claims of anti-Asian discrimination really objections to race-based affirmative action and therefore anti-black speech? Is support for free speech a reflection of white privilege and, therefore, anti-minority?

An example of the zero-sum game from Europe may be instructive: In Turkey, it is a crime to say the Armenian genocide occurred, while in France, it is a crime to say it didn't.

Delgado and Stefancic are leading figures in the "critical race theory" movement, a legal approach that sees law through the prism of race. They are, of course, correct in pointing to racial inequality in all areas of American life and to the abuse some minority students suffer at the hands of some insensitive white students. In response, they want universities to adopt restrictive speech codes that "promote equality" and that are enforced by administrators who "must be attuned to the nuances of insult and white supremacy."

The authors posit two irreconcilable positions on free speech. The first, which they characterize as the totalist approach, tolerates no compromises on freedom of expression. This is, of course, a straw man. No one disputes the appropriateness of neutral restrictions on expression, based on time, place, manner and other objective criteria. For example, a university could impose restrictions on the late-night use of loudspeakers or on disruption of classes or religious services, but not on the content of speech. The second, which they call the equality approach, argues that free speech cannot truly be free without equality among the speakers: "Free speech, in other words, presupposes equality." This approach rejects the "marketplace of ideas" as unequal: It is "slanted against people of color and other minorities." It follows from this assessment that minorities need affirmative action speech codes to level the playing field. They cite a Supreme Court affirmative action case — Grutter v. Bollinger — in support of this dubious proposal.

The authors reject the neutral principle under which any restrictions on speech must be applied equally to all groups, because at bottom they are making a case for "free speech for me but not for thee" — "me" in this case being minorities. Although they occasionally talk the talk of neutrality, they refuse to accept content-neutral rules that do not give preference to one group over another. Nor are they prepared to acknowledge that what some regard as hate speech may lie at the center of the First Amendment.

Among the book's most fundamental flaws is its placement of Nazi hate speech at the periphery of the First Amendment, when by any reasonable definition it sits at its very core. Nude dancing, hard-core porn and commercial advertising may be peripheral to the political concerns of the First Amendment. Still, according constitutional protection to these genres of speech may be necessary to build a wall around the core to protect it from the slippery slope. But what could be more central than advocacy by the Nazi Party of a political program for America? Nazi speech is no more peripheral than communist speech. It may be more hateful and more dangerous, but to call it peripheral is to misunderstand the essential purpose of the First Amendment.

The authors trivialize the classic arguments in favor of freedom of expression — from Aristotle to Thomas Jefferson to Henry Louis Gates Jr. — as "thought-ending clichés," "shibboleths," "facile," "tired maxims," "wooden, mechanistic," "paternalistic," "remarkably devoid of merit" and "seriously flawed." They counter them with cliches of their own, such as that "adopting hate-speech rules," like those in force in some other countries, would make "America . . . even more American."

The case for censorship is even older and tireder than the case for free speech. Freedom of speech may be a better road to equality, as Martin Luther King Jr. and the abolitionists and suffragettes before him demonstrated. It may be a bumpy road, but it may be the worst possible approach to expression, as Winston Churchill once said of democracy, "except for all those other forms that have been tried from time to time."

Must We Defend Nazis?
Why the First Amendment Should Not Protect Hate Speech and White Supremacy

By Richard Delgado and Jean Stefancic

New York University. 164 pp. $14.95 paperback