Davenport, Iowa The emerging media narrative on the 2008 presidential campaign is simple, as media narratives always are. Republicans, egged on by the the McCain campaign, are angry. Maybe dangerous. With furrowed brows media big-shots are wondering aloud if John McCain should "tamp down" -- new cliche alert -- his supporters before they begin to physically harm their political foes.

The new media narrative was born after McCain's town hall in Waukesha, Wisconsin, on Thursday, where several voters voiced the frustration and, yes, anger in questions to McCain. And several voters shouted their criticism of Obama, echoing McCain from the stage.

And from that, we were told, Republicans are filled with "rage." Of course, there were 5,000 people at the event; maybe two or three dozen shouted criticism of Obama. The vast majority never shouted criticism.

But in the last 36 hours, we've seen three examples of real anger on the left. And as the old media axiom has it, three makes a trend.

This morning at a McCain rally here, a bearded young man in the crowd responded to a McCain critique of Barack Obama by shouting: "You're a liar John!" He then hoisted a young woman with an antiwar poster onto his shoulders and began yelling antiwar gibberish as McCain tried to continue his speech. When McCain supporters ripped up the woman's sign, she unfolded another one and the spectacle continued.

Earlier, at a rally in Philadelphia, Obama praised John McCain's service to America and called for a civil debate over the final days of the campaign. He was lustily booed by his angry supporters.

And yesterday, at a McCain rally in LaCrosse, Wisconsin, another angry heckler shouted "Liar" and other insults at McCain from the crowd.

Can we expect stories on this disturbing trend? Don't bet on it.