But in reality it's either Edwards or Kucinich - Gravel having been seen on YouTube throwing rocks into a pond, which rather disqualifies him, except as a Web 2.0 media event.
So it's Kucinich, because of nagging doubts that Edwards is the Left's - er - Clinton, and perhaps isn't being entirely sincere about his populist positioning.
But while Edwards is a progressive for where the US is right now, he's a moderate progressive after three decades of having the "middle" being pulled toward the right ... I'm not sure where he'd lie in the European political spectrum. I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.