Here's a quick news quiz: What do the Jena 6, San Diego Padres outfielder Milton Bradley, and the protests against Mahmoud Ahmadinejad's appearance at Columbia University have in common?
In all three cases, Americans appear to have forgotten the difference between hateful speech and hateful action. And when we lose sight of that distinction, we lose what should be most distinctive about America itself.
Start with the six African American teenagers who were arrested for attempted murder last December in the beating of a white classmate in Jena, La. The arrests came after several other racial incidents in Jena, including white students hanging nooses from a tree at their school to warn blacks against sitting under it. Blacks complained that the whites who hung the nooses were simply suspended from school, while the African Americans who beat their classmate faced criminal charges.
But there's an excellent reason for punishing these behaviors differently: One involved symbols; the other involved fists. Although the attempted-murder charge against the black teens was clearly excessive (and since reduced), they committed an obvious act of physical violence. The noose-hanging white students didn't.
Nor did the umpire who hurled a slur at Mr. Bradley last Sunday. Bradley charged the umpire and fell to the ground, sustaining a season-ending knee injury. "I'm not going to stand pat and accept this," he told reporters, "because I didn't do nothing wrong."
Nothing wrong? Like the racist noose-hangers in Jena, the umpire should be disciplined if he said something gratuitously insulting to Bradley. But no slur can excuse or justify Bradley's response. A hateful act is always worse than a hateful word.
And that brings us to Mr. Ahmadinejad. Protesters converged upon Columbia on Monday to condemn the university for hosting the Iranian president, who gave a rambling talk to a packed auditorium. Ahmadinejad has a reputation for hate speech, including Holocaust denial, and he did not disappoint.
Rather than acknowledging the Holocaust, he called for more research to establish whether it happened. And he insisted that there were no gays in Iran, evoking laughter from the audience.
So should the university have invited this bizarre speaker in the first place? According to Columbia's critics, some ideas are so offensive, hateful, or simply inaccurate that they must be barred from universities altogether.
Wrong. By agreeing to host Ahmadinejad, Columbia did not communicate any special approval for the man or his ideas. Instead, it signaled its adherence to a much larger principle: free speech itself.
Unlike a high school, which caters to minors, the university is made for adults. And unlike a baseball diamond, where players are governed by league rules of decorum, the university is an intellectual free-for-all.
Or, at least, it should be. Universities exist to create and disseminate knowledge. And the best way to do that is to admit and analyze every point of view, no matter how scurrilous or objectionable. Sustained inquiry and discussion will separate the intellectual chaff from the wheat. Administrative fiat won't.
Suppose Columbia decided to allow all speakers on campus, except the ones that the university deemed truly hateful. Would a member of the Jewish Defense League be kept out, because Palestinian students might find his speech hateful? Would we exclude a speaker from Hamas, because Jews would be similarly offended?
Recall that in 1961, the University of California at Berkeley barred Malcolm X from appearing on campus. Communist speakers were banned until 1963, when the university decided to allow "radical" speakers if they were balanced by "traditional" ones. Students' own speech was closely regulated, too. They could not solicit money or members for any political organization, because allowing such activity might give the university's imprimatur to their cause.
Sound familiar? Today, the critics of Columbia sound a lot like Berkeley's administrators forty years ago. If you allow someone to speak on campus, the argument goes, you're giving them implicit approval. And some people are so reprehensible that they don't deserve it.
But we can't trust university administrators – or anyone, really – to make this distinction.
That's why students protested at Berkeley in the Free Speech Movement of 1964, the first salvo in a great national wave of campus dissent. Across the country, Americans won the right to say whatever they wished at our universities.
It would be a shame to turn back now, all in the name of shielding ourselves from words that are too hateful for some of us to hear.
• Jonathan Zimmerman teaches history and education at New York University. He is the author of "Innocents Abroad: American Teachers in the American Century."