In the fall of 1997, students at Cornell University in New York stole 500 copies of the Cornell Review, a conservative campus newspaper, and burned them. The students were protesting the paper’s inclusion of an editorial cartoon suggesting that African Americans have a disproportionate number of abortions. This incident followed a similar event the previous spring, when 200 copies of the Review were destroyed in response to the publication of a parody piece on Ebonics (Black English). These events—and a string of similar instances that have taken place on college campuses nationwide in recent years— illustrate that the ideal of free speech, so simple in theory, is often controversial in practice.

America’s Founding Fathers believed so strongly in the right to free speech that they codified it in the First Amendment to the U.S. Constitution, which states in part, “Congress shall make...