DES MOINES, Iowa — It was the 2011 Iowa State Fair, and things were going well for Mitt Romney.
After poor reviews of his visit four years earlier, Romney had dressed more casually and trimmed down his entourage. He gamely flipped pork chops, posed with a 2,000-pound pig and admired an intricately carved butter cow.
Then he stepped up to the fair's political soapbox.
With one leg propped up on a bale of hay, Romney sparred with a group of hecklers. When one interrupted the former Massachusetts governor to argue for tax increases on large businesses, Romney testily replied, "Corporations are people, my friend."
Democrats quickly seized on that line, using it to define Romney as a cold, out-of-touch businessman. That narrative ultimately helped doom his effort to unseat President Barack Obama.
Romney's remark serves as a cautionary tale for the nearly two dozen Democratic presidential candidates who will descend on the Iowa State Fair this week.
The fair is a rite of passage for anyone with White House aspirations, a photo op that often serves up funny and weird moments - and sometimes political catastrophe. It "is just dotted with land mines," said David Kochel, Romney's senior adviser in Iowa during his 2012 run. The "corporations" remark "ended up being one of them."
The 11-day event is a political obstacle course that's been damaging to a number of candidates, establishing a narrative that when set is often hard to shake. And it will be especially challenging this year, as candidates struggle to strike the right tone while the nation contends with the aftermath of a violent weekend.
In 2007, former senator Fred Thompson, R-Tenn., launched a last-minute bid for the GOP nomination, built around his aw-shucks appeal to working-class voters. He undermined that message when he showed up at the fair in what a television reporter initially described as a pair for Gucci loafers. (Thompson, a former television and film star known for his stint on "Law & Order," later clarified that they were Salvatore Ferragamo shoes.)
Thompson's "Gucci shoes" haunted him for the rest of his campaign, which went belly up a few months later.
In 2003, then-Sen. John Kerry, D-Mass., arrived at the fair just days after he'd been labeled snooty for ordering a Philly cheesesteak with Swiss cheese instead of the usual Cheez Whiz. Robert Gibbs, a former White House press secretary working for Kerry at the time, recalled going ballistic when he spotted the senator buying a strawberry smoothie with an umbrella in it.
"Somebody get a [expletive] corn dog in his hand now!" Gibbs yelled to an aide.
But Kerry got into trouble anyway. During his tour of the fair, he met a man who had just moved to Iowa from Massachusetts. "Why?" the senator asked, in what aides later insisted was a dry attempt at a joke.
The man didn't laugh.
"You can't come to the fair and fake it," said former senator Tom Harkin, D-Iowa. "People here have what they call their 'phony antenna.' Are you real or are you just putting on a show? Are you trying too hard to be like us?"
"They look very closely for a politician to do or say something that is indicative of what their real personality is," Harkin said. "People aren't easily fooled."
Some missteps have been more damaging than others. Perhaps no one understands that better than Joe Biden, whose bid for the 1988 Democratic presidential nomination was derailed by a plagiarism scandal that began during his first Iowa State Fair appearance.
During his closing remarks at a candidate debate held at the fair in August 1987, Biden quoted without attribution several phrases from a speech previously given by Neil Kinnock, a British Labour Party politician. Biden had used the lines before in stump speeches, crediting Kinnock, but later said he forgot.
The ensuing scandal led to revelations that Biden had also been accused of plagiarism in law school.
He quit the race about a month later.
Watching this crop of Democratic contenders at the fair could also offer some early signs of organizational strength. Since Romney's speech in 2011, campaigns have made a practice of packing the area around the soapbox with volunteers and supporters, some claiming seats hours ahead of time. In 2015, one of the earliest signs of Bernie Sanders' growing strength in Iowa was when his soapbox speech attracted a few thousand people.
Hillary Clinton skipped the soapbox, citing security concerns, but toured the fair with a chaotic scrum of several hundred people that included members of the media, volunteers, staff, supporters and security. But in a foreshadowing of the tumultuous general election to come, it was Donald Trump who stole the show.
As Clinton emerged from an agriculture building where she had paid her respects to the butter cow, her entourage was suddenly distracted by Trump's low-flying helicopter, which flew in slow circles around the fairgrounds, a scene reminiscent of "The Wizard of Oz."
Harkin, who was with Clinton, recalled staring up at the strange scene, unable to believe what he was seeing. "I thought nobody was going to buy this. Iowans don't like showy types or people flaunting their wealth," Harkin recalled. "How little did I know?"