Howard Dean took one bite of a deep-fried Oreo and dismissively pitched the rest into the garbage.
Mitt Romney famously flipped a pork chop, right into the gravel. And John Kerry capped his Iowa State Fair fare with a strawberry smoothie, rather than a cold beer that offered a chance for him to seem connected with regular folks.
"I wouldn't order a smoothie," said Jeff Link, a veteran Iowa Democratic operative. "That kind of summed the whole thing up right there."
The state fair, a quadrennial presidential prerequisite stop, is a cultural obstacle course more fraught with pitfalls than opportunities to sway the narrow band of voters who will attend the state's kickoff caucuses in less than six months. Starting Thursday, more than 20 Democratic presidential candidates will begin weighing nutritionally questionable food choices and navigating media flocks resembling crows on a French fry — all while trying to seem both presidential and comfortable with the folkways of Middle America.
This year, selections that include bacon-wrapped corn dogs and a monstrosity called the hot beef sundae pose particular challenges for Hawaii Rep. Tulsi Gabbard, a vegetarian, and New Jersey Sen. Cory Booker, who keeps vegan.
"There are few breakthrough moments, and the memorable ones are often not good," said John Norris, who managed John Kerry's 2004 Iowa caucus campaign.
Joe Biden, who will return to the fair Thursday, would know.
In August 1987, he lifted passages of a speech by British Labor Party leader Neil Kinnock's speech without attribution during a 1987 Democratic candidates' debate at the fair. The revelation punctuated previous questions of plagiarism that shadowed Biden and led ultimately to his early drop from the 1988 race.
It was an epic fair fail. But presidential history also is sprinkled with winning performances.
In 2007, Barack Obama's romp through the Midway with his family — and iconic turn on the bumper cars with his daughter Sasha — cast a glow over the rising Illinois senator.
But for every such gauzy memory, there are more clunkers, or worse yet, permanent scars.
In 2007, amid heavy expectations, former Republican Sen. Fred Thompson famously made his Iowa debut by attending the Iowa State Fair wearing a pair of $500 Gucci loafers.
That was after he was chauffeured down the voter-packed Grand Concourse by golf cart to meet his escort, the notoriously frugal Iowa Sen. Chuck Grassley. Thompson stayed aboard the cart, waving only occasionally at the many star-struck voters who recognized him.
The episode was hardly a black eye. But, just as Kerry's smoothie contributed to questions about the Massachusetts senator's connection to regular folk, Thompson's less-than-enthusiastic embrace of the time-honored Iowa tradition clashed with the down-home Southerner he often portrayed as an actor.
Some candidates this year may be better-prepared than others. Former Colorado Gov. John Hickenlooper will avoid Kerry's oversight. Hickenlooper, who founded a successful brewery, will pour beers for fairgoers at the craft beer tent.
On Wednesday, Sen. Amy Klobuchar joked about her love of a good state fair, noting she attends the fair in her neighboring home state of Minnesota every year — and that she, too, has experience with butter sculptures.
"One thing we have in common, of course, as strong dairy states, is the butter carving. I am looking very forward to seeing your butter cow at the Iowa State Fair. I am going to have to decide if it holds a candle to our Princess Kay of the Milky Way statue," she said, referencing Minnesota's iconic butter bust.
One test, the soap box speech, has carried potentially dangerous repercussions, thanks to the once idealistic notion of a former Des Moines Register editor.
"I think the challenge is the soap box speech, getting through it without incident or statements that come back to haunt you," said former Iowa Gov. Tom Vilsack.
In 2002, then-political editor Blair Claflin mused about promoting the Register while drawing candidates, otherwise given to holding court while roaming the fairgrounds, to a single location.
Claflin's idea, a take on 19th century street-corner oratory, would become the Register's Political Soapbox. Now entering its 18th year, the once simple straw-bale and poor-quality microphone setup has evolved into a constructed stage that campaign organizers pack with supporters in hopes of projecting momentum.
"Under the best of circumstances, I figured it might become a quaint Iowa State Fair tradition, requiring just a microphone and a few bales of hay," said Claflin, now director of sustainability communications at Cummins Inc. in Indiana. "More than 20 presidential candidates over a week speaking from a stage? I never imagined anything like that."
In 2015, would-be presidential nominees Hillary Clinton and Donald Trump skipped the Register venue during their fair tours. Trump made a decidedly Trumpian entrance, on his private helicopter. But he had the crowd when he provided children a ride.
Their decision to skip the speechifying may have been influenced by Romney's contentious episode at the Register venue in 2011, when the former Massachusetts governor got in a testy back-and-forth with protesters, eliciting one of the 2012 campaign's most memorable, if awkward, lines.
"Corporations are people, my friend. Of course they are," Romney countered to a protester angry that corporations weren't paying higher taxes. "Everything corporations earn ultimately goes to people."
The exchange, captured by the crowd of national media on hand, punctuated the narrative that the wealthy former venture capitalist was out of sync with voters.
Then there are achingly awkward moments that point to a candidate's long odds.
Bob Graham sang from the Register venue, "You've got a friend in Bob Graham," a tune he'd attributed to his 40 years of success in Florida politics. The smattering of applause became a metaphor for Graham's presidential campaign, which ended before the caucuses.
But what a candidate eats often is the most scrutinized, if certainly visual, image at the fair, home to deep-fried everything.
Not to be outdone by anyone, then-Ohio Gov. John Kasich wolfed down not one but three pork chops at the must-stop Iowa Pork Producers complex.
Despite the minefield the fair presents, candidates can gain something beyond a strategic advantage in Iowa if they listen to the people they meet, said veteran Republican strategist Bob Haus.
"People are honest. They'll tell you what they think because they're on their turf, and often have a few beers in them," Haus said. "So you honestly get feedback. A lot you like, and some you may not."