I don't know what Robert Theobald would have thought of the Seattle gathering of the World Trade Organization. The futurist, who died last Saturday in Spokane at age 70, might have thought the delegates to the 135-nation confab mistaken to pin too much hope on an ever-expanding economy, but he might have welcomed the multinational attempt to impose some order on international trade.

But one thing I know for sure: Bob Theobald would have been outraged at the violent attempts on the part of some anti-WTO demonstrators to bust up the meeting. He might have had some sympathy with their anti-business phobia (he feared that pushing the limits of economic production was a fool's errand and a mortal danger to the environment). He might have agreed with the aims of the most radical demonstrators in Seattle. But I can tell you he wouldn't have watched their tactics and murmured: "I understand."

Those two words--I understand--may constitute the most dangerous phrase in the English language, Theobald told me on one of his fly-through Washington visits, back before his energies were sapped by the esophageal cancer that finally took his life.

Why? Because understanding unacceptable behavior encourages unacceptable behavior, and the result is the destruction of civility, trust and even conversation that could help build community and help us solve our problems.

"We've got to learn to reject our own extremists," he said.

I thought about that conversation when I heard some of the more restrained among the Seattle demonstrators taking pains to make clear that the great majority of them were not interested in violent confrontation. That, they said, was the work of a small, well-organized minority. I could almost hear Theobald's "most dangerous phrase."

I hear it, or sentiments close to it, all the time. "I understand" why some black men behave irresponsibly, why inner-city kids are so dangerous, why people react the way they do to rudeness in traffic, why animal-rights advocates splash fake blood on fur coats, even why some frustrated workers "go postal." Our understanding increases in direct proportion as we share the sentiment, experience the insult, partake of the frustration and fear.

As Theobald noted, we are perfectly willing to censure the outrageous behavior of those on the other side. It's the rough ones on our side who reduce us to silence--and understanding.

The much-traveled author and lecturer (born in India, he grew up in the United Kingdom and lived in New Orleans before moving to Spokane a few years ago) said the idea of reining in one's own extremists occurred to him while he was thinking about violence in Northern Ireland.

"There just aren't that many hard-core IRA people," he said at the time. "Certainly not enough to sustain the level of terrorism and violence we've seen. But there is a significant number of people who say, 'I wouldn't do that, but I understand why they do.' And that understanding gives them the political and moral cover they need."

Nor is it just outrageous behavior that Theobald thought we need to reject, but outrageous language as well. I thought of that when I heard a young demonstrator on TV equating the (apparently reluctant) tear-gassing of the most aggressive of the anti-WTO crowd with Saddam Hussein's "use of chemical weapons against his own people."

Well, what's the harm in a little rhetorical overkill?

Said Theobald, outrageous rhetoric can pave the way for outrageous behavior and make it seem not so outrageous after all. Spiking trees (to destroy a timberman's chain saw and perhaps kill him) seems less unreasonable in the context of rhetoric that equates the harvesting of forests with the destruction of earth. Bombing abortion clinics becomes a tenable counteroffensive if the rhetoric equates abortion to the wholesale slaughter of innocent children.

Theobald thought there would be less terrorism, less tree-spiking and less hate crime if the allies of the extremists would make clear the limits on acceptable behavior.

And, at least in some cases, it might promote the conditions for dialogue and negotiation that can lead to real change--if we could just learn to stop saying: I understand.