Sen. Bernie Sanders, speaking at a policy forum here Tuesday, identified a singular roadblock to achieving success on a host of progressive policies. It's American oligarchy. Sanders ... argued that the small number of multi-billionaires who now have power over the country's economic, political and social life is one issue out there which is so significant and so pervasive that, unless we successfully confront it, it will be impossible to succeed on any of these other important issues." The solution, he said, is not only ending voter suppression, "extreme gerrymandering" and overturning the Citizens United Supreme Court decision, which helped pave the way for super PACs, but moving toward automatic voter registration. He called for Wall Street, billionaires and big corporations to start paying their "fair share" in taxes, and for "substantially" increasing the estate tax. The annual conference ... was billed in part as an opportunity for speakers to "preview and sharpen the best arguments for rejecting far-right conservatism and for enacting progressive policies" at all levels of government. During his speech Tuesday, Sanders ... said the current "grotesque level" of income and wealth inequality is immoral and causing "massive suffering."