David Cole takes a look at suggestions for banning various forms of offensive speech and comes away unconvinced:

Such proposals to regulate hate speech—whether “two-pronged” or not—are flawed, for principled, legal reasons, as well as strategic, political considerations. As a legal matter, any attempt to penalize speech because of its offensive content contravenes the First Amendment’s bedrock principle that the government should not be in the business of defining what messages are permissible or impermissible. Arguments for regulating hate speech often take the same form as those made by defenders of laws prohibiting flag burning: if the content of the expression is offensive, and the speech itself is deemed of negligible value, it should be suppressed. But the last thing we need in a democracy is the government—or the majority—defining what is or is not a permissible message.

Second, defining “hate speech” in a way that draws a clear and enforceable line between that which deserves protection and that which can be prohibited is an elusive, and probably impossible, task. Ruthven’s proposal distinguishes between criticism and “insult,” an approach eerily reminiscent of the one Turkey’s Prime Minister Tayyip Erdoğan has adopted in defending the prosecution of journalistsfor “insulting” Turkey. Waldron’s proposal draws similarly vague lines between speech that offends, which he would protect, and speech that denigrates the human dignity of individuals or groups, which he would not. Canada prohibits “any writing, sign or visible representation” that “incites hatred against any identifiable group.” Ireland prohibits “blasphemous” speech that is “grossly abusive or insulting in relation to matters held sacred by any religion.”

Such laws empower the government, or a jury, to draw lines between legitimate criticism, satire, and public comment on the one hand, and “insulting,” “abusive,” or “hateful” speech on the other. Is there any reason to be confident that government officials or juries will do a good job of this? And as long as the lines are so murky, many people will be compelled to steer clear of legitimate expression that some official or jury might, from its own viewpoint, deem over the line after the fact: this would stifle free speech and lead to self-censorship. Ruthven himself seems ambivalent about whether Rushdie’s depiction of Mohammed in The Satanic Verses is “insulting,” and therefore should be prohibited, or an example of artistic criticism that should be protected.

He concludes:

There is a place for limits. I am a professor. I do not tolerate, in my classroom, disrespectful speech of any kind, because it interferes with the learning environment that I seek to foster. I am also a father, and have a similar view with respect to the need for respectful speech around the dinner table. A responsible newspaper publisher might well decline to print an article that its editors were convinced was likely to spark violence. But these limits are not imposed by law, but by social norms and ethics, which are in turn informed by discussion, dialogue, and culture. Such norms are quite powerful, and ensure that for the most part, people do not use their freedom of speech irresponsibly. In those isolated instances where freedom is exercised irresponsibly, it is far better to employ more speech to condemn it—as President Barack Obama did recently in response to the YouTube video—than to empower the state to limit speech by punishing dissidents deemed hateful or insulting.