At an event in New Hampton, Iowa last month, Democratic presidential hopeful was asked about her Senate vote in favor of calling the Iranian Revolutionary Guard a terrorist organization.
"Why should I support your candidacy ... " Randall Rolph asked, "if it appears you haven't learned from your past mistakes?"
Clinton answered the question -- and suggested that "somebody obviously sent" it to him, since she had "been asked the very same question in three other places." Rolph said he was offended by the implication and that the question came from his own research.
Now Clinton is once again dealing with the concept of planted questions, though this time it is her own campaign that is coming under fire.
A sophomore at Grinnell College named Muriel Gallo-Chasanoff told CNN she was encouraged by a Clinton staffer in Newton, Iowa to ask the candidate a question about climate change -- and was discouraged from asking the question she had come up with.
She also said she overheard another questioner discussing how the campaign had asked him to ask a specific question about jobs. Another man, Geoffrey Mitchell, said he was approached at a Clinton event in Iowa in April and asked to ask a question about war funding.
The Clinton campaign admitted that the question asked by Gallo-Chasanoff was planted by a staffer, but said Clinton "had no idea who she was calling on, and this is not acceptable campaign process moving forward. We've taken steps to ensure that it never happens again."
According to Dan Schnur, however, such tactics are typical for campaigns -- and not just Clinton's. Schnur was 's communications director in the 2000 campaign and now teaches at University of California, Berkeley and The University of Southern California.
"I don't think in either party I've ever seen a campaign that holds question and answer events that doesn't arrange for some questions," says Schnur. "That's not to say every question is prepared. That's not to say the candidate knows every question coming. But it's pretty standard practice."
Schnur says campaigns approach reporters in a similar way -- suggesting that if they ask a candidate about immigration, for example, they might get a newsworthy response. Opposition campaigns also send operatives to pose particularly difficult or slanted questions -- which is what Clinton seemed to think Randall Rolph was up to when he asked his question about Iran.
But if all campaigns use these sorts of tactics, why is Clinton being singled out?
"Every candidate faces one double standard or another, especially if it reinforces the preexisting impressions about that candidate," says Schnur. "There is already a suspicion among the first concentric circles of politics that Hillary Clinton is over-programmed, so this becomes a bigger story for her than it would for (Barack) or (John) ."
A longtime political consultant who spoke to CBS News agrees.
"People are going after her because she's the frontrunner, and also because there are questions of whether she is evading," says the consultant. "Is she talking straight and being forthcoming? If she is staging questions, you've got to wonder."
CBS News political consultant Nicole Wallace, a former aide to President Bush, disputes the notion that staged questions are common practice.
"Do campaigns go in and say, 'We want people to talk about their experiences with social security?' Sure," Wallace says. "It's not unheard of to steer questions. But scripting of a question is where any candidate is going to run into trouble."
When questions are planted, she says, "It's a recipe for disaster for a politician who is trying to appear authentic." Wallace notes that campaigns are constantly trying to balance their desire to control a candidate's message with their desire for the candidate to be seen as spontaneous and genuine.
Mr. Bush and his staff have been criticized for pre-screening audience members in an effort to make sure questions come from supporters, particularly when he was traveling the country in support of his Social Security plan in 2005. On Saturday, Edwards compared Clinton's tactics to Bush's.
"That's what George does: George Bush goes to events that are staged, where people are screened," said Edwards, according to Politico. "That's not the way democracy works in Iowa."
Obama also weighed in, saying pre-screening questioners is "not a practice that we've ever engaged in and it's not a practice that we ever plan to engage in."
Republican presidential hopeful also said his campaign does not screen questions.
"Frankly, in a town hall setting like this, and every setting I'm in, we take all the questions, and we don't know who the questioners are," said Romney. "Sometimes there are planted questions that come from other campaigns or people that have a particular interest. But you know what? You take them all, and you respond honestly to the questions you get. That's part of the process."
By Brian Montopoli