FiveThirtyEight: Webb would make a good anti-Clinton

[Sprouts Farmers Market ✘]

That's a very interesting article, and I think he would probably be able to appeal to disaffected leftists if Sanders is not in the race and they want a serious 2nd challenger because O'Malley - no matter how liberal he is - just doesn't the immediate appeal because he doesn't have socialist next to his name or anti-Wall Street crusader like Warren. Outside of Sanders, I would think they could settle for whoever is in 2nd place. I also think a lot of liberals still idolize Hillary and want her to be the first female president despite her positions so it's obviously highly unlikely they switch unless there is mainstream buzz about Wall Street throwing money at her and it gets taken seriously.

You would think Schweitzer could have been pretty successful as a liberal with moderate appeal rather than attempting to get a moderate to appeal to the left. I think the energy positions on coal and Keystone XL (and to extent guns but not really) turns a lot of real liberals off though (and the comments about southern men didn't help though I think they'd get over that). It's similar to Huntsman '08 who was very far right on economic matters - far more right wing than Santorum or Bachmann could ever dream to be -  but the support for gays kind of killed him with authoritarian conservatives/rural Religious Right and he was stuck with only moderate appeal - and just barely at that. Both Schweitzer and Huntsman are theoretically great candidates but one issue killed them.

Webb could pile up a good deal of the vote as an anti-Hillary, but I still don't see a moderate white man picking up more than half of the true left vote even if he were the only alternative to the first female presidential nominee. If he got 20-25% as a 2nd place (and Hillary was down around 40-50), I wouldn't be shocked, but Sanders is going to be getting the 10% of leftists in reality.
20-25% is far more than he deserves in a Democratic primary as a 1 term Senator so he should take that if he can get it.