Elizabeth Warren is, I think, a great demonstration of the kind of movement-oriented model-wielding power from within the Senate. Over and over, she's rallied tons of people to battles that they don't normally get involved in.

When [Bernie] Sanders was challenged about how he would pass his visionary ideas after he became president, he talked about if lawmakers look out the window and they see a million people marching, it changes their calculus. Well, here's an opportunity to continue working to organize these million people even if he is not the one in office.

I think changing the Democratic Party platform [at the convention] is a great place to start. It should include expanding Social Security, a $15 minimum wage, and breaking up too-big-to-fail banks on Wall Street - among other Sanders priorities.

We've just gone through this period of years where the players in the game were at least written about as being a Democratic administration, establishment Republicans, and then the rabble-rousing radicals of the tea party. And it was like a three-way negotiation between them. But we are going to enter an era where there's a physical, powerful, vibrant progressive movement that will, I think, be able to exercise power in the same way as the right-wing and the right does.

Elizabeth Warren is, I think, a great demonstration of the kind of movement-oriented model-wielding power from within the Senate. Over and over, she's rallied tons of people to battles that they don't normally get involved in.

An organization is great if you have a clear vision to be able to make it powerful. If you don't, an organization can kind of sap energy that could go elsewhere.

The most important thing will be building a bench of powerhouse progressives in elected office and in the next administration. [Bernie] Sanders has an enormous spotlight that he can shine on champions that are following the Sanders path of really building from the left.