On Global Warming, MoveOn Voters Pick Edwards:
“In a recent virtual town hall meeting on climate change with the Democratic presidential candidates sponsored by MoveOn.org, former Senator John Edwards renewed his call to reduce greenhouse gas emissions in the United States by 80 percent by 2050 and said that his plan for getting there was the “most aggressive” of any of his opponents.”
Metaphor 
No, I think it's because he's not as dramatic as Clinton or Obama. He'll move up when Americans start to lose their made for TV interest in those two, and realize they – the voters – don't have the stones to vote for a woman or a black.
I don't know why Edwards so persistently hangs way back in third place. Is it because he's too slick, a la a trial lawyer?