Someone turns on the TV and sees a politician being interviewed. He's never voted for her party, he disagrees with what she's saying and he doesn't like her hair. What does he do? He discovers her email address and lets her know what he'd like to do to a bitch like her.
Not long afterwards, the same man reads something that annoys him in a newspaper or more likely (as he doesn't see why he should pay to read this stuff) on its website. In no time he's emailing again, casting slurs on the columnist's ethnicity, appearance and sexual performance.
Sadly, these are everyday occurrences in Britain and the US, where public discourse has been poisoned by rage, hate and envy. Public figures have been dehumanised to a point where abuse is routine, death threats far from uncommon, and a handful of people occasionally try to carry them out.
I'm not just thinking about poor Gabrielle Giffords, the congresswoman shot in Arizona last weekend, along with several constituents queuing to talk to her. In this country, a young Muslim woman is serving a life sentence for stabbing a Labour MP, Stephen Timms, after she read hate-filled material on the web from an Islamist cleric. After last year's attack on Timms, a Lib Dem peer and former MP called on serving MPs to improve their security; Nigel Jones, as he then was, was attacked 11 years ago by a man with a samurai sword during a constituency surgery in Cheltenham. His aide, Andrew Pennington, was killed.
Like most columnists, I get hate mail and occasional threats, and I've read some of the abuse that's regularly sent to MPs. It's part of a wider phenomenon which Barack Obama addressed in a measured speech last week, talking about living in "a time when we are far too eager to lay the blame for all that ails the world at the feet of those who think differently than we do".
It was in some ways a brilliant speech, capturing the sombre mood. But I fear that the President's call to "expand our moral imaginations, to listen to each other more carefully" went over the heads of people whose vision of public life is akin to a gore-stained gladiatorial arena. (Yes, I do mean Sarah Palin.)
Obama praised a concept I'm very keen on but haven't heard much in recent years: civility. One of its meanings is politeness, but it also indicates a state of mind in which we're all members of society and have obligations to each other – a far cry from what we've got at the moment.
When, I wonder, did people arrive at the conclusion that disagreeing with someone is synonymous with hating them? It exists alongside another vile assumption, the idea that all ideological opponents are liars, cheats and thieves. Among the online-abuse community, it's beyond question that Julian Assange's accusers are lying feminist slags.
I'm not arguing for legal restrictions on free speech, which has to include the possibility of saying things other people find offensive; the distinction I'm making is between robust public debate and personal abuse. The latter creates an atmosphere of cynicism and distrust which undermines the legitimacy of democratic politics.
"We may not be able to stop all the evil in the world, but I know that how we treat one another is entirely up to us," Obama declared. It's a long-overdue challenge to all the bloggers, shock jocks and ranters whose sole purpose is to humiliate and wound.