The impolitic aside, the indelicate joke, the sudden flash of pique, the slip of the salty tongue. Political campaigns, the ultimate in packaging and polish, live in fear of unguarded moments like those.
The latest comes from John Kerry (search).
Television played and replayed the moment Wednesday when the Democratic presidential candidate, his back to the camera but his voice being recorded, told a Chicago worker that President Bush's Republicans are "the most crooked ... lying group I've ever seen."
For sure, the Democrats have been after Bush for allegedly misleading the country on the justification for going to war with Iraq, and they've spoken darkly of misbehavior arising from Republican links to corporate interests such as Halliburton Co (search).
But mainstream candidates don't accuse each other of flat-out lying lightly, and the Kerry camp gamely tried to explain the remark by suggesting it was not, precisely, about Bush himself, but rather about GOP critics of the senator in general.
"This is language you don't ordinarily use in public," said Kathleen Hall Jamieson, an authority on campaign rhetoric with the Annenberg Public Policy Center. She was referring to presidential candidates in the main, noting that accusations of lying flew loosely from the lips of also-rans in the Democratic primary race and from others over the years.
Presidential campaigns have occasionally been thrown off stride by flaps over comments that were meant to be private and turned out to be anything but. Bush, in a faux pas also set in Illinois, stood on a podium with running mate Dick Cheney in the 2000 campaign and used an obscenity to describe a reporter in the nearby press area.
"I regret everybody heard what I said," Bush remarked later, which was not quite the same as regretting saying it. Jamieson recalled that the Bush campaign got knocked off message for a few days as a result.
More often, however, the problem in politics is not about a forgotten open mike but a case of mouths getting ahead of minds.
Howard Dean's almost hysterically happy speech after coming third in the Iowa Democratic caucuses contributed to his campaign's sudden fade.
Back in 1988, Bob Dole was marked as an angry man after his biting comment to GOP primary rival George Bush, this president's father: "Stop lying about my record."
And Spiro Agnew (search), as Richard Nixon's running mate in 1968, did his boss no favor in a Detroit speech in which he said: "If you've seen one city slum you've seen them all."
President Reagan made an unintended art of the unguarded crack, frequently uttered while warming up for the remarks he really wanted Americans to hear. He called Democratic opponent Michael Dukakis an "invalid," described Polish leaders as "a bunch of no-good, lousy bums" and characterized his economy as "a hell of a mess."
Most famously, he joked into an open microphone: "All right, my fellow Americans, I am pleased to tell you today that I have signed legislation that will outlaw Russia forever. We begin bombing in five minutes."
Kerry hasn't had moments remotely like those, but he has stepped out of the package at times.
In a Rolling Stone interview geared to readers who don't expect Boy Scout language, he described Bush's Iraq policy in profane terms, saying, "Did I expect George Bush to f--- it up as badly as he did? I don't think anybody did." He shrugged off a White House request that he apologize.
And he let his frustration show when reporters kept asking him about Dean this, Dean that, back in September when the former Vermont governor's campaign was ascendant.
Kerry finished a news conference and, not thinking about a live mike, walked away muttering "Dean, Dean, Dean, Dean."
Campaigns might not like unscripted episodes but Chris Lehane, a former aide in the Kerry campaign and strategist for Al Gore in 2000, said they "will really be a window into these candidates' personalities," and can help a campaign if they are handled well.
On Wednesday, Kerry mingled with workers at a Chicago sheet metal company after a speech, and one of them urged him to take on Bush. Kerry responded, "We're going to keep pounding. These guys are the most crooked, you know, lying group I've ever seen. It's scary."
Marc Racicot, chairman of the Bush-Cheney campaign, said the statement was "unbecoming" of a presidential candidate and sought an apology.
Apologies often come after the worst transgressions. Bill Clinton gave one in 1992 after saying that then-New York Gov. Mario Cuomo, a fellow Democrat, was a "mean son of a bitch" who "acts like" a Mafia figure.
But that message got him in less hot water than the messenger who went public with it. He made the comments in a phone call recorded by Gennifer Flowers (search), who played the tape as evidence she had an affair with him.