Incivility, yes. Indecency, no.

Nothing is harder to achieve in a time of turbulence than clarity. In an inflamed moment, there may be no greater public service than the drawing of a distinction. In 1953, for example, Sidney Hook published a book called Heresy, Yes—Conspiracy, No. His subject was the threat posed by communism, and his argument was that an open society needed to distinguish between heresy, which was to be celebrated, and conspiracy, which was to be condemned and fought. In the aftermath of the shooting of Gabrielle Giffords, we could use a similar distinction. The one we propose is: Incivility, yes. Indecency, no.

Even if the assassin was just a madman without any ideological inflection, it is hard to escape the feeling that there is a poison in our public life. In the wake of the tragedy in Arizona, we have found ourselves in a national discussion—overdue, perhaps, at this late date in the history of contemporary vitriol—about the nature of our political discourse. The left has accused the right of fostering a wild and menacing political climate—a climate in which a mentally ill man, who might have been politically motivated, would target a Democratic congresswoman for assassination. The right has retorted that the murder was prompted entirely by mental illness, not at all by the political weather, and that there is nothing much amiss with this weather in the first place. Everybody is once again playing their parts in the very script that, in our collective revulsion at the horror in Tucson, we are supposed to be reckoning with.

There is no denying that we have been living in an era of stridency—the last three American presidents, Democrat and Republican, have been reviled by their opponents not for being wrong, but for being illegitimate—and the economic crisis has further raised the temperature. Hardship is not reason’s friend, even if reason is never more necessary. But the sermonizing left is failing to acknowledge that political debate ought to be intense, tempestuous, and even rude, while the complacent right (with the bizarre exception of Roger Ailes, who told his talking heads at Fox to “tone it down,” and with a single phrase made a joke of his talking heads) is refusing to take any responsibility for rhetoric that goes perilously far into the realm of insult and innuendo.

First, a word on behalf of incivility. It is an important element—and when the stakes are high, an inevitable element—of healthy political disputation. Uncivil discourse is not the same thing as murderous discourse; in some hands, it is even compatible with rational argument. We must beware a certain goody-goodyishness about the character of our public discussion. There is no shame in passion. Our politics were raised on the expectation of bitter conflict—Madison’s “faction,” Hamilton’s “jarrings of parties” that “promote deliberation and circumspection”—and the introduction of an inhibition upon the full-throated expression of beliefs and preferences would confuse and even cripple our democracy, which is the system of government by debate.

At its best, incivility can even be an exalted thing. There are ideas and forces that need to be opposed loudly and completely, without mincing words. In an ideal world, for instance, Barack Obama would be deeply uncivil on the subject of human rights when he meets with Hu Jintao next week at the White House; but then, he has done more than anybody to make partisanship disreputable. If the repeal of health care reform is noxious to you, why is it wrong for you to say so in the most ringing terms? Should liberals respond politely to climate change denial, or know-nothing economics, or immigration hysteria? Of course not. And it would be hypocritical not to concede that conservatives should do the same about what they most abhor. Or is demagoguery just eloquence with which we disagree?