Does Bernie need to win the White House to lead the movement and can he lead the movement from the White House? I think the answer to both questions is no. I say this as a 2016 supporter and current fan. He has made the Democratic Party a working class party again. It’s an invaluable service and one he can best continue performing from the outside.
Warren is running to do specific things for a specific role (she’s got a plan for that). I think that makes her a far more effective potential president. There is a reason she would have been an effective agency head. She knows how power works and how to wield it effectively on behalf of people instead of donors.
Warren bridges the growing populist/expert divide in our party. Her economic program is for the people and not the elites, but she relies on expertise to actually make it happen. She knows how to pay for her agenda and push it through Congress.
Like Bernie, she recognizes the Clinton and Obama administrations weren’t tough enough on the villains who wrecked our economy. Like Hillary, she’s a policy wonk who knows how systems work and how to change them. We need Warren inside the White House to put her plans into action and Bernie outside the White House to keep her and Congressional Democrats honest.