Libertarian: Pallas sextile Mercury, ruled by Jupiter (square the Nodes and Sun).
Authoritarian: Pallas trine Pluto which is semisquare Pallas ruler Jupiter.
This is strong on authoritarianism (you'd have to be, to be Socialist) but the Nodal square to Pallas' ruler is a wildcard which can strongly mitigate the Pluto effect. This is a "whistleblower" pattern a la Edward Snowden, and there's a chance that Sanders actually has a conscience.
Collectivist/Leftist: Venus tightly quincunx South Node.
Capitalist: nothing visible here.
No surprise here.
Conservative: North Node quincunx Moon ruler Mars, and possibly Moon.
Liberal: Neptune quincunx Moon ruler Mars, and possibly Moon.
Strongly mixed signatures tend to veer to the liberal side of things, and may be an "environmentalist" signature.
Mixed Pallas + Strongly Collectivist + Culturally Liberal --> "Principled" Socialist
The chart reflects the man.
There probably isn't a Bloodbath Formula here, which in my book helps put him ahead of everyone but Rand Paul in the race for the throne. Sanders as President might get suckered into enabling the military-industrial complex, but I suspect he's not an active supporter.
Sanders' political Achilles' Heel might be the fact that he has, like an idiot, publicly written about rape fantasies. If Sanders gains any true traction, this is probably what Hillary and the Establishment will use to grind him into a fine red paste. As for the psychology that drives such politically-inconvenient impulses, I would say it's the clear Rapist Formula on his chart:
1. Pallas trine Pluto which is semisquare Pallas ruler Jupiter.
2. Venus tightly quincunx South Node.
3. Mars rules and conjoins Moon.
4. Sun square Jupiter; Jupiter sextile Mars; Mars parallel Sun.
5. Jupiter square Neptune and the Nodes.
We usually get killers in the White House. "Rape Fantasy Guy" would probably be an improvement.
North Node conjunct/parallel Neptune, both conjunct Sun, all in Virgo: a man whose destiny is to represent a dream of how things should work.
Mercury trine Saturn/Uranus conjunction: giving voice to rebellion.
You know things are fucked when an openly-Socialist, semi-closeted misogynist is one the better candidates in the presidential race. But, as our Islamic brethren say, "the enemy of my enemy is my friend". Give 'em hell, Bernie.
Addendum November 2015: Sanders is a hypocritical, pro-war piece of shit. I was wrong.