Add Newark, N.J., Mayor Cory Booker to the long list of political stand-ins for both President Barack Obama and Republican Mitt Romney who've veered wildly off message in a presidential contest notable for its attention-grabbing gaffes.
An Obama backer, Booker forced the president's campaign into damage-control mode over the weekend when he called its attack on Romney's tenure at a private equity firm "nauseating." It didn't take long for Republicans to highlight the comment and for the Democratic mayor to try to clean up the mess he caused by releasing a YouTube video in which he said it was fair for Obama to make Romney's business record a campaign issue.
Obama weighed in Monday as the dust-up lit up social network sites, calling Booker an "outstanding mayor" but insisting he would continue to talk about Romney's experience at Bain Capital.
"It's important to recognize this issue is not a distraction," the president said. "It's part of the debate we are having in this election."
The episode, which delighted Republicans while causing a headache for Obama, illustrated the difficulty a presidential candidate faces in controlling his or her message in the era of YouTube and Twitter. It also raised questions about how much campaigns should be held responsible for what their supporters — known as "surrogates" in political-speak — say or do.
"Maintaining message discipline with surrogates has always been a challenge of the modern campaign. In the era of social media it is an exercise in futility," said Chris Lehane, a spokesman for Democrat Al Gore's 2000 presidential bid. "Most surrogates are significant people in their own right with their own views, own constituencies and own press corps, and are used to speaking for themselves and not conditioned to the idea that whatever they say or do will become attached to a presidential candidate."
That was the case for Booker, who has an active social media presence and is eyeing a run for statewide office in New Jersey, where many bankers and private equity investors live.
His effort to soften the blow of his comments Sunday on NBC's "Meet the Press" didn't seem to satisfy Obama's team. Campaign strategist David Axelrod told MSNBC a day later that Booker was wrong and Romney's experience at Bain "speaks to an economic theory that isn't the right economic theory for the country."
Meanwhile, a gleeful Republican National Committee bought ads on Twitter drawing attention to Booker's comment, and launched an "I Stand with Cory" petition that links signers to a video him.
Almost everyone who speaks on behalf of a candidate is dubbed a surrogate, whether they are close advisers, television pundits or donors eager to make their opinions known. Some surrogates hew closely to the campaign's talking points. Those who don't quickly find themselves in the hot seat.
That's what happened to Romney strategist Eric Fehrnstrom, who told CNN in March that the campaign would "hit a reset button" once Romney became the Republican nominee.
"It's almost like an Etch A Sketch," Fehrnstrom said, referring to the children's toy. "You can kind of shake it up, and we start all over again."
The remark, which immediately went viral on the Internet, seemed to reinforce a narrative that Romney has long battled — that the former Massachusetts governor is a shape-shifter who can't be trusted as a true conservative. Campaign advisers insisted Fehrnstrom was talking about the logistics of running a general election campaign, not Romney's core principles. But Democrats used the moment to assail Romney anyway.
Celebrities — often helpful in drawing attention and cash to a candidate — can also cause headaches for campaigns.
Talk-show host Bill Maher, who has contributed $1 million to a super political action committee supporting Obama, posted a message on Twitter on Monday that referred to Romney's Mormon faith as a "cult." Obama's campaign has said Romney's religion should not be part of the campaign.
Maher also stirred controversy last month when he used an expletive on his HBO program to argue that Romney's wife, Ann, hasn't worked outside the home. Republicans called on Obama to distance himself from Maher and said the super PAC, Priorities USA Action, should return the celebrity's money.
That dust-up was similar to another from last month, when Obama supporter Hilary Rosen said Ann Romney "had never worked a day in her life." Obama's campaign swiftly repudiated the comment and sought to distance itself from it even though Rosen has no role in the campaign. Obama's team feared the absence of a strong repudiation of Rosen's remarks would both turn off women voters and signal that attacks on wives were acceptable.
Romney's campaign had its own problems with a celebrity surrogate when Ted Nugent, a rock music star, made provocative comments about Obama.
Nugent met with Secret Service representatives after a speech to the National Rifle Association in which he referred to Obama's "evil, America-hating administration" and urged voters to "chop their heads off in November." Nugent added, "If Obama is elected, I will either be dead or in jail."
Romney's campaign, which sought and publicized Nugent's endorsement, distanced itself from his comments. "Divisive language is offensive no matter what side of the political aisle it comes from," Romney spokeswoman Andrea Saul said. "Mitt Romney believes everyone needs to be civil."
That wasn't enough for Democratic National Committee Chair Debbie Wasserman Schultz, who called on Romney to "condemn Nugent's violent and hateful rhetoric immediately."
Super PACs, which can raise and spend unlimited sums and are legally prohibited from coordinating with the candidates they support, have emerged as surrogates of a sort and have further complicated efforts by campaigns to stay on message.
Romney was forced to answer for — and repudiate — an ad campaign under consideration by a conservative-leaning super PAC showcasing Obama's relationship with his controversial former pastor, the Rev. Jeremiah Wright. Joe Ricketts, the billionaire founder of TD Ameritrade Securites, had been weighing a $10 million contribution to the effort but said after it became public that he did not want to participate in such an effort.
Neither did Romney, who said: "It's the wrong course for a PAC or a campaign."
Get the latest from NBC 4 New York anytime, anywhere. Follow us on Twitter, Facebook and Google+. Get our apps here and sign up for email newsletters here. Get breaking news delivered right to your phone -- just text NYBREAKING to 639710. For more info, text HELP. To end, text STOP. Message and data rates may apply.