Here is how it is supposed to work: candidate is endorsed by surrogate, preferably someone well-known, well-spoken, energetic and loyal. Surrogate travels the country, spreading candidate's message far and wide.
"A good surrogate serves as a validator," said Kevin Madden, former press secretary and senior adviser to former Massachusetts Gov. Mitt Romney.
"They can go out there and (speak) to a constituency that recognizes them as an expert on (an) issue, and that constituency can say, 'Here's somebody that's associating themselves with this candidate. I want to associate myself with this candidate, too.'"
An ideal surrogate is someone who is recognizable, trusted by a large number of voters as an expert on certain issues, and who can garner the attention of the media. The surrogate is the candidate's representative, his or her spokesperson.
The surrogate's mission is to communicate the campaign's message forcefully and articulately. The old maxim that was taught to medical students for many centuries applies equally to surrogates: Primum non nocere, or first, do no harm.
"The more people speaking on behalf of the candidate, the greater risk that someone's going to veer off message," said Dan Schnur, a McCain campaign strategist in 2000. "So, you train them as best as you can (and) cross your fingers."
One prime danger is that, when asked a question, a surrogate will be tempted to offer his own opinion. No matter how worthy or insightful or interesting the surrogate may consider what he has to say, this is not always a good idea.
"Anytime you put someone out there to speak for the campaign, you risk attaching your campaign's name, your campaign's reputation, [on] words that may be controversial," Madden said.
That's what happened last week when former Texas Republican Sen. Phil Gramm, an ardent supporter of Sen. John McCain, R-Ariz., was asked by a Washington Times reporter about the nation's economic woes.
Gramm replied, "You've heard of mental depression? This is mental recession," then, squirting a stream of fuel onto the blaze, he added, "You just hear this constant whining, complaining. We sort of became a nation of whiners," he said.
This was a classic example of an off-the-chain surrogate.
Not only were Gramm's remarks controversial -- he seemed to say people who were worried about the economy were a bunch of whiners, and that the perception of economic woes was largely in a figment of people's imagination -- but they undercut the message Sen. John McCain, R-Ariz., had been assiduously promoting all week: that he understands that people are worried about the economy and that his proposals are the answer.
Using the traditional euphemism of campaign idiom, one McCain campaign official called Gramm's remarks "a distraction."
McCain had no choice but to distance himself from his own surrogate and friend.
"Phil Gramm does not speak for me. I speak for me," McCain said, adding that Gramm, whose name has -- or now, had -- been mentioned as a possible Treasury secretary in a McCain administration: "I think that Sen. Gramm would be in serious consideration for ambassador to Belarus, although I'm not sure the citizens of Minsk would welcome that."