A few decades ago, most politicians knew they had to be civil to members of the opposing party in order to legislate, so it was important to forget about the mudslinging that inevitably occurs in an election campaign. Most knew that, as the English political philosopher Michael Oakeshott said, "political education means learning how to participate in a political conversation."

Nowadays, according to many observers, there is very little cross-party conversation going on in Congress. A recent book argues that both chambers are poisonously partisan — so awash in mistrust, suspicion and anger that Congress is no longer an effective legislative body.

The lack of conversation in Congress is not a surprise — given the low level of conversation in the general public. But hasn't it always been difficult for Americans to have a political conversation? Since the founding of the republic, political differences frequently have generated sound and fury.

Yet it does seem more difficult to discuss political questions than it did two decades ago. An obvious reason comes to mind: the protracted war in Iraq. "I detest war; it ruins conversation," the French philosopher Bernard de Fontenelle said. A war that is not going well is bound to stir up anger. It is impossible to calmly discuss Iraq if someone yells: "Do you know how many Americans died in Iraq this month?"

Yet even if the war ended tomorrow, it would still be hard to have a political conversation because the rise of the Internet has eroded the art of conversation. It is difficult to disagree politely in the virtual world, where one only sees words on a screen (or those stupid smiley faces). Positions tend to harden. There is no nuance that comes from tone of voice and gesture.

To be a good conversationalist one also needs to be a good listener. This is a skill one learns by being with others — not by spending hours a day in front of a computer screen. The English novelist Henry Fielding defined conversation as "that reciprocal Interchange of Ideas, by which Truth is examined, (and) Things are, in a manner, turned around, and sifted." It is much harder to turn around and sift a question in the virtual world than in face-to-face encounters.

In "The De-Voicing of Society: Why We Don't Talk to Each Other Anymore," John L. Locke warns: "With no access to our species' social feedback and control mechanisms, there will be nothing to keep misunderstanding, incivility and dishonesty from creeping into our daily life at unprecedented levels."

To be sure, the Internet has enabled people to communicate in countries where they lack freedom of speech and assembly, but in general it promotes political polarization. The blogosphere is an arena for angry minds, since many people search for Web sites that stoke their political anger.

Television talk shows offer predictable, semi-scripted conversation. On some talk shows, guests promote their latest products; on others, political pundits offer soundbites. On therapeutic talk shows, the guest "shares" his or her story with the audience, and then the host or hostess dispenses advice.

Contemporary language is often an enemy of conversation. There is the impoverished language of text-messaging and the foul-mouthed swaggering language of rappers.

Though the forces nourishing conversation in the United States are weaker than the forces undermining it, there are some positive signs. There has been an increase in discussion groups about a wide variety of subjects. Recently, a high school student said in the Washington Post: "Over time, people are going to get sick of talking to people on the computer. I just think people will want to spend more time with each other — without the wall of technology."

It would be a good if Americans spent more time with each other, but many also need to make more of an effort to be polite — to restrain their angry passions. Politeness is something that requires willpower. Samuel Johnson, the 18th-century English writer, was naturally irascible, but he tried to control his irascibility because he thought politeness was the glue that held society together. "Depend upon it, the want of it never fails to produce something disagreeable to one or other."

Alas, in America today many people enjoy being impolite. They think it is a sign of integrity to express oneself vehemently. Moreover, angry authors, angry columnists, and angry talk-show hosts usually do well in the marketplace. The climate for conversation is not good, so good conversationalists — people who listen attentively and disagree politely — may become an endangered species.

Stephen Miller is the author of "Conversation: A History of a Declining Art." He wrote this for the Philadelphia Inquirer.