How has John Edwards become the "poor man's candidate?" Because perception is reality. Image guru's can sometimes make a rich man look poor and a poor man look rich. Here are a few past examples:
The son of a Quaker blacksmith, Herbert Hoover was a self-made man who became one of the greatest humanitarians of the 20th century. Prior to being elected president, Hoover worked to help those suffering from the Great Mississippi flood, and gave millions away to help war-torn Europe. According to Wikipedia, "The the Finns have even added the word hoover, meaning "to help," to their language in honor of his two years of humanitarian work."
Hoover's successor, FDR, was a rich kid from Hyde Park, New York. Because of the Great Depression, Hoover (the self-made man/humanitarian) is remembered as being "uncaring," while FDR (the rich man) is celebrated as the "poor man's president."
A more recent example is in the world of heavyweight boxing and, to be more specific, the Muhammad Ali/Joe Frazier trilogy.
"Smokin' Joe" was a dark-skinned son of a sharecropper who grew up on the mean streets of Philadelphia. Conversely, Muhammad Ali was an educated middle-class kid who went to the Olympics and defied the draft. Ali called Frazier "ugly," "a gorilla," and an "Uncle Tom." Ali won the PR battle for "streed credibility." Frazier became a "poseur." Go figure. (Ali was a PR genious who did the same thing to George Forman in Africa).
Perception is reality. It's a crazy world, but if FDR can be "the poor man's president" -- and Ali can have more "street cred" than "Smokin' Joe," then I guess John Edwards can get away with being "the poor man's candidate." Of course, RFK did a pretty good job of being the "poor man's candidate, too."
Come to think of it, maybe it's the hair?