"The issue we're dealing with is actually the struggle to rebuild American democracy," Sanders said in an interview at a Capitol Hill bistro. "Economically, over the last 40 years, we've seen a middle class in this country disappearing.
"Ninety-nine percent of all new income generated today goes to the top 1 percent. The top one-tenth of 1 percent owns as much wealth as the bottom 90 percent. Does anybody think this is the kind of economy we should have. Do we think it's moral?"
Read More10 questions with Bernie Sanders
Sanders acknowledges the long odds against his attempt to upset former Secretary of State Hillary Rodham Clinton and capture the 2016 Democratic presidential nomination. But he's interested in advancing his ideas even if he doesn't win. And at a moment when rank-and-file Democratic voters are gravitating toward more robust economic populism, Clinton's campaign is watching his efforts closely.
The one-time mayor of Burlington decided months ago to pursue a campaign only if he had confidence that it wouldn't be a counter-productive flop. "If I do badly, and I don't run a good campaign, and we don't get our message out, and we don't bring people together, it reflects not just on me, but on the ideas that I'm talking about," Sanders said.
But he added: "A couple months ago, I was in California, a beautiful sunny day. We had 500 people coming out at a union hall. I went to Austin, Texas—we had about 600 people coming out. I was in Las Vegas—we had 300 people coming out. Went to Chicago—we had 400 people. So I am sensing that based on that trip and trips that I made to Iowa, New Hampshire, that there is more disconnect and more anger at the establishment—the corporate establishment, the political establishment, the media establishment."
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And of course no one represents the Democratic political establishment more than Clinton. Where she moves cautiously to consolidate support, he speaks with abandon to the visceral concerns of Democratic liberals about some titans of business and finance.