When campaign strategists and political analysts go out on camping trips — they do, you know — they end the night by gathering around the campfire and telling stories of a terrifying, unstoppable, voracious and mysterious force that preys on vulnerable political campaigns: the Preference Cascade.

“The Preference Cascade only stalks totalitarian regimes,” the skeptics say. “I’ve read Glenn Reynolds’ field reports and eyewitness accounts, about how the Preference Cascade needs a lot of unexpressed emotion to feed upon. ‘A totalitarian regime spends a lot of effort making sure that citizens don’t realize the extent to which their fellow-citizens dislike the regime. If the secret police and the censors are doing their job, 99 percent of the populace can hate the regime and be ready to revolt against it — but no revolt will occur because no one realizes that everyone else feels the same way.’ You just don’t have that same group dynamic in American society.”

“Ah, but how many early-favorite candidates have tried to run on inevitability?” says the old timer, tossing a stick onto the campfire. “Everybody you know is voting for somebody, because everybody they know is voting for that guy. Nobody’s really giving the other candidates a serious thought, until something unexpected happens — and then the favorite finds out his support was a mile wide and an inch deep.”

Another consultant pipes up.

“An old-timer I know said he had the Preference Cascade gobble up one of his candidates once,” he said quietly. “He said it was like a nightmare. You think you’re doing fine, you have enough folks whose default setting is to vote for your guy, and then . . . BOOM. Suddenly, day by day, things get worse. The undecideds start jumping onto the bandwagon of the other guy, and they just won’t stop. They tune out your guy and just about everything he says. Attack ads that normally would be called ‘tough’ or ‘hard-hitting’ start getting mocked as ‘desperate’ or ‘flailing.’ Volunteers stop showing up. Your early voters taper off. It used to be nobody mocked your guy, and suddenly he’s the butt of the jokes of the comics.”

A shiver ran down the spines of the younger campaign strategists. “Does the Preference Cascade give any warnings?”

The old timer piped up again. “It sniffs out weakness and vulnerability in a well-known candidate’s job approval numbers,” he said, pointing his finger. “Sometimes voters avert their eyes from an incumbent’s flaws — he’s in there, they hope he does well. Sometimes they won’t like what he’s doing, but they’ll give him the benefit of the doubt. They’ll come up with all kinds of excuses. But the Preference Cascade’s catalyst triggers this change, and suddenly all of that repressed disapproval comes tumbling out. It’s not that the candidate has suddenly irked these voters so much; it’s that they’ve been irked for a while and they suddenly feel okay expressing it. And once they see more people expressing it, they express it louder themselves — swaying the people around them. It’s like a feedback group that gets louder and more intense and faster as time goes on.”

By now the young campaign consultants around the campfire were wide-eyed.

The youngest found his voice, just loud enough to whisper, “Once the Preference Cascade starts hunting your candidate, how do you stop it?”

The old timer looked the young consultant in the eye with a grim, haunted look.

“Nobody knows.”

. . .

. . . In other news, Gallup’s tracking poll has shifted from a tie on October 9 to a 52 percent to 45 percent lead for Romney today.